The ~ symbol indicates my commentary on the quotations.

The Lord Jesus Christ: “But I have prayed for you, so that your faith may not fail, and so that you, once converted, may confirm your brothers.” [Luke 22:32]

First Vatican Council: “So the fathers of the fourth Council of Constantinople, following the footsteps of their predecessors, published this solemn profession of faith: ‘The first condition of salvation is to maintain the rule of the true faith. And since that saying of our Lord Jesus Christ, “You are Peter, and upon this rock I will build my Church” [Mt 16:18], cannot fail of its effect, the words spoken are confirmed by their consequences. For in the Apostolic See the Catholic religion has always been preserved unblemished, and sacred doctrine been held in honor. Since it is our earnest desire to be in no way separated from this faith and doctrine, we hope that we may deserve to remain in that one communion which the Apostolic See preaches, for in it, is the whole and true strength of the Christian religion.’ ” [Vatican I, Pastor Aeternus, chapter 4, n. 2]

“Indeed, their Apostolic teaching was embraced by all the venerable fathers and reverenced and followed by all the holy orthodox doctors, for they knew very well that this See of St. Peter always remains unblemished by any error, in accordance with the divine promise of our Lord and Savior to the prince of his disciples: ‘I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren’ [Lk 22:32].” [Vatican I, Pastor Aeternus, Chapter 4, n. 6; on the freedom from grave error of the Apostolic See.]

“This charism of truth and never-failing faith was therefore divinely-conferred on Peter and his successors in this See so that they might discharge their exalted office for the salvation of all, and so that the whole flock of Christ might be kept away by them from the poisonous food of error and be nourished with the sustenance of heavenly doctrine. Thus the tendency to schism is removed and the whole Church is preserved in unity, and, resting on its foundation, can stand firm against the gates of hell.” [Vatican I, Pastor Aeternus, chapter 4, n. 7.]

~ The First Vatican Council infallibly taught that each Roman Pontiff has the charism of truth and of never-failing faith, for the purpose of keeping the flock of Jesus Christ away from the poisonous food of error. This necessarily implies that no Pope can teach material heresy, as then the flock would be fed with the food of error. And it necessarily implies that no Pope can commit formal heresy, as then his personal faith would have failed.

~ To what extent are the decisions of the Roman Pontiff protected from the poisonous food of error? This is true so much so that we can say that the Apostolic See is essentially “unblemished by any error”. We can also say, in another phrasing of the same teaching, that “in the Apostolic See the Catholic religion has always been preserved unblemished”. But since Vatican I also decided that the teachings of the Roman Pontiff are only infallible, that is, only without all error, when certain conditions are met, we must interpret “unblemished by any error” as referring to any grave error. Less than grave errors in non-infallible decisions of doctrine or discipline, which do not require the full assent of faith, and which permit limited licit dissent, would then not be considered blemishes on the See or on the religion.

Constantinople III, the Letter of Pope Saint Agatho:
“because the true confession thereof for which Peter was pronounced blessed by the Lord of all things, was revealed by the Father of heaven, for he received from the Redeemer of all himself, by three commendations, the duty of feeding the spiritual sheep of the Church; under whose protecting shield, this Apostolic Church of his has never turned away from the path of truth in any direction of error, whose authority, as that of the Prince of all the Apostles, the whole Catholic Church, and the Ecumenical Synods have faithfully embraced, and followed in all things; and all the venerable Fathers have embraced its Apostolic doctrine, through which they as the most approved luminaries of the Church of Christ have shone; and the holy orthodox doctors have venerated and followed it, while the heretics have pursued it with false criminations and with derogatory hatred. This is the living tradition of the Apostles of Christ, which his Church holds everywhere, which is chiefly to be loved and fostered, and is to be preached with confidence….”

“For this is the rule of the true faith, which this spiritual mother of your most tranquil empire, the Apostolic Church of Christ, has both in prosperity and in adversity always held and defended with energy; which, it will be proved, by the grace of Almighty God, has never erred from the path of the apostolic tradition, nor has she been depraved by yielding to heretical innovations, but from the beginning she has received the Christian faith from her founders, the princes of the Apostles of Christ, and remains undefiled unto the end, according to the divine promise of the Lord and Saviour himself, which he uttered in the holy Gospels to the prince of his disciples: saying, “Peter, Peter, behold, Satan hath desired to have you, that he might sift you as wheat; but I have prayed for thee, that (thy) faith fail not. And when thou art converted, strengthen thy brethren.” Let your tranquil Clemency therefore consider, since it is the Lord and Savior of all, whose faith it is, that promised that Peter’s faith should not fail and exhorted him to strengthen his brethren, how it is known to all that the Apostolic pontiffs, the predecessors of my littleness, have always confidently done this very thing….” [Pope Saint Agatho, Letter accepted into the Acts of the Sixth Ecumenical Council, Constantinople III.]

Constantinople III, approving the Letter of Agatho: “The chief Prince of the Apostles was fighting on our side: for we have had as our ally his follower and the successor to his see: and the paper and the ink were seen, and Peter spoke through Agatho” (Actio xviii.).” [Pope Leo XIII, Satis Cognitum, n. 13, citing the Third Council at Constantinople.]

~ Pope Saint Agatho’s Letter was accepted into the Acts of the Council, making his teaching the teaching of a Pope, of a Saint, and of an Ecumenical Council. The Letter teaches that the faith of Peter and his successors will not fail, because it is the faith of Christ within them. Then, under the protecting shield of the Roman Pontiffs, the Apostolic Church “has never turned away from the path of truth in any direction of error.” This is the living Tradition, which the Church holds everywhere and since Her earliest days, since the very day when Christ spoke those words to Peter (Lk 22:32).

~ The Apostolic Church “has never erred from the path of the apostolic tradition, nor has she been depraved by yielding to heretical innovations”. And the reason for this, teaches Pope Saint Agatho, is that the Church “has received the Christian faith from her founders, the princes of the Apostles of Christ,” meaning from the Roman Pontiffs. For Peter is the Prince of the Apostles of Christ, and each successive Roman Pontiff is also a Prince of the body of Bishops, the successors to the other Apostles. Then each Roman Pontiff, each Pope, has this same charism of never-failing faith. Thus, the words of Christ are true in every generation, that each Roman Pontiff is the Rock on which the Church is founded, and the gates of Hell cannot prevail over the Church because they cannot prevail over the Roman Pontiff:

Pope Leo XIII: “neither against the rock upon which Christ builds His Church nor against the Church shall the gates of Hell prevail.” [Pope Leo XIII quoting Origen; Satis Cognitum, n. 12.]

~ But if the Roman Pontiff could fall into heresy, or could err gravely in doctrine or discipline, then the indefectibility of the Church would be lost. For the authority of the Pope, “the whole Catholic Church, and the Ecumenical Synods have faithfully embraced, and followed in all things.” Then, too, “all the venerable Fathers have embraced its Apostolic doctrine, through which they as the most approved luminaries of the Church of Christ have shone; and the holy orthodox doctors have venerated and followed it….” If the Apostolic See could err gravely or teach heresy, then this teaching, which has many different wordings in the quotes above and below, would not be true. As it is, this same teaching on the preservation of the Apostolic See from grave error and the never-failing faith of the Roman Pontiff has been taught again and again, by Popes, Saints, and Councils.

~ But after Pope Saint Agatho died, did not the Third Council of Constantinople (the Sixth Council overall) condemn Pope Honorius I as a heretic? Even though the Council accepted the teaching of Pope Saint Agatho, some Council fathers rose up, after his death, and again tried to blame Honorius for the problems of their day by accusing him of heresy. But after the Council ended, the approval of the new Pope, Saint Leo II was needed. Nothing is of a Council unless approved by the Roman Pontiff.

Vatican II: “A council is never ecumenical unless it is confirmed or at least accepted as such by the successor of Peter; and it is prerogative of the Roman Pontiff to convoke these councils, to preside over them and to confirm them.” [Second Vatican Council, Lumen Gentium 22]

~ Pope Saint Leo II refused to condemn Honorius as a heretic, and instead changed the charge from heresy to negligence. Pope John IV, Saint Robert Bellarmine, and Saint Maximus the Confessor agree that Honorius was not guilty of heresy. Then the dogma of the never-failing faith of the Roman Pontiff requires us to hold that no valid Pope has ever taught or committed heresy.

Pope Saint Leo II, changed the charge against Pope Honorius I from heresy to negligence, within the same three Latin letters that formally approved of the Council’s Acts:
1: Pope Leo II to the Bishops of Spain: “Honorius, who did not immediately extinguish the flame of the heretical teaching, as would befit the apostolic authority, but supported it by his negligence“.
2: Pope Leo II to the king of Spain: “Honorius of Rome, who allowed the immaculate rule of apostolic tradition that he had received from his predecessors to be stained….”
3: Pope Leo II to the Roman emperor: “And, we in like manner, anathemized the inventors of the new error, namely, Theodore, Bishop of Pharan, Cyrus of Alexandria, Sergius, Phyrrus … and also Honorius, who did not purify this apostolic Church by the doctrine of the apostolic tradition, but rather he allowed the immaculate [Church] to be stained by profane treason.”

Catholic Encyclopedia: “Pennacchi, followed by Grisar, taught that by these words Leo II explicitly abrogated the condemnation for heresy by the council, and substituted a condemnation for negligence.” [Chapman, J. (1910). Pope Honorius I. In The Catholic Encyclopedia. New York: Robert Appleton Company.]

~ As for the assertion that the Church was stained by the heresies that Honorius failed to extinguish, this is true in one sense, but not another. The true Faith and the Roman Pontiffs never taught the heresies at issue (one energy; one will). But the heresies did spread among the faithful and gain much popularity, before being condemned and extinguished. Only some members of the Church were stained by these heresies; the Roman Pontiff never held or taught these errors. Saint Sophronius was the chief opponent of Monoenergism in Honorius’ day, and yet he never accused the Roman Pontiff of heresy, and he remained obedient to the Pope. Never was Saint Sophronius asked by Honorius to abandon his defense of the faith, nor to adhere to heresy.

The Council of Florence: “the most illustrious profession of the Roman Church about the truth of the faith, which has always been pure from all stain of error.” [Council of Florence, Session 13; 30 Nov. 1444.]

Lateran IV: “He dictated a letter, which he signed with his own hand, in which he firmly confesses that he holds the faith held by the Roman Church, which is by God’s plan the Mother and Mistress of all the faithful.” [Fourth Lateran Council, n. 2. On Abbot Joachim]

~ The Roman Church, also called the Apostolic See, has always been free from “all stain of error”. And this is why the Roman Church is “by God’s plan the Mother and Mistress of all the faithful.” Then the faithful are all required to submit to the teaching of the Roman Pontiff, and to his decisions on discipline, for this same reason, that he cannot err gravely in doctrine or discipline. That is why Peter and his successors are the Rock of never-failing faith on which the Church is founded. That is why it is necessary to salvation for the faithful to submit to the doctrine and discipline of the Roman Pontiff:

Pope Boniface, Unam Sanctam: “Moreover, that every human creature is to be subject to the Roman pontiff, we declare, we state, we define, and we pronounce to be entirely from the necessity of salvation.” [Pope Boniface VIII, Unam Sanctam, n. 9; confirmed by the Fifth Lateran Council.]

Lateran V: “It arises from the necessity of salvation that all the faithful of Christ are to be subject to the Roman Pontiff.” [Fifth Lateran Council, 19 December 1516]

Lateran V: “As we read in another place, the person who abandons the teaching of the Roman pontiff cannot be within the Church….” [Fifth Lateran Council, 19 December 1516]

~ Subjection to the Roman Pontiff can only be required for salvation (absent the invincible ignorance of non-Catholics) if the Roman Pontiff himself can never be a heretic, nor teach heresy. For heresy is opposed to the faith that leads to salvation. And God could never require subjection to a heretic as part of the path of salvation. Thus, as so many Popes and Saints teach, the Pope is never-failing in faith and can never succumb to heresy.

~ The Fifth Lateran Council also approved and confirmed the document Unam Sanctam, which teaches that the Roman Pontiff is judged by no one but God:

Pope Boniface VIII, Unam Sanctam: “Therefore, if the earthly power goes astray, it will be judged by the spiritual power; but if a lesser spiritual power goes astray, it will be judged by its superior; and truly, if the highest power goes astray, it will not be able to be judged by man, but by God alone. And so the Apostle testifies, “The spiritual man judges all things, but he himself is judged by no one.” [1 Corinthians 2:15]

“But this authority, even though it may be given to a man, and may be exercised by a man, is not human, but rather divine power, having been given by the divine mouth of Christ to Peter, and to him as well as to his successors, by Christ Himself, that is, to him whom He had disclosed to be the firm rock, just as the Lord said to Peter himself: ‘Whatever you shall bind,’ [Matthew 16:19] etc. Therefore, whoever resists this authority, such as it has been ordained by God, resists the ordination of God. (Rom 13:2) [Pope Boniface VIII, Unam Sanctam, n. 7-8.]

~ Many Catholics assume that, while the Roman Pontiff cannot err at all in what is infallible (dogma; dogmatic facts), that he might err to any extent, even to the extent of heresy, otherwise. But we can already see from the teachings above — and there are many more below — that Popes cannot err gravely in doctrine or discipline. For the Apostolic See, that is, the exercise of the authority of the Pope over doctrine and discipline, is unblemished by any grave error. And that is why the Roman Pontiff is not to be judged by anyone but God. No one would be given such a role in the Church, so that he is above judgment, unless God keeps him from grave error.

Saint Ambrose: “Could not Christ, who confided to him the Kingdom by His own authority, have strengthened the faith of the one whom He designated a Rock to show the foundation of the Church?” [St. Ambrose, De Fide, bk. 4, n. 56]

Pope Saint Lucius I: “The Roman Apostolic Church is the mother of all Churches and has never been shown to have wandered from the path of Apostolic tradition, nor being deformed, succumbed to heretical novelties according to the promise of the Lord himself, saying, ‘I have prayed for thee, etc.’ [Lk 22:32]” [Pope Saint Lucius I, Martyr, 253-254, Epist. I ad Episcopos Hispaniae et Galliae]

Pope Saint Felix I, 269-274, on the Roman Church: “As it took up in the beginning the norm of the Christian Faith from its authors, the Princes of the Apostles of Christ, She remains unsullied according to what the Lord said: ‘I have prayed for thee, etc.’ [Lk 22:32]” [quoted by Saint Robert Bellarmine. On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) p. 157-158, Mediatrix Press]

Pope Damasus I: “The First See, therefore, is that of Peter the Apostle, that of the Roman Church, which has neither stain nor blemish nor anything like it.” [quoted in Ray, Stephen K., Upon This Rock (Modern Apologetics Library: Ignatius Press) p. 85]

~ The three Popes above, teach that the Roman Church, the mother of all the other Churches in the one universal Church on earth, has never wandered from Apostolic tradition, never succumbed to heresy, remains unsullied, is the norm of the Christian faith, and has neither stain or blemish. And the reason given by Lucius and Felix is that the Roman Pontiff has the unfailing faith provided by the prayer of the Lord Jesus (Lk 22:32).

~ But did not Peter fail in faith when he denied Christ three times? Yes, he did. But that is why Christ said “I have prayed for you” and “once converted”, because the gift of never-failing faith was given to Peter at a later time, after his conversion. Christ prayed for him so that later, after his fall, Peter would be converted into a Rock of never-failing faith. This gift of never-failing faith is given to each Roman Pontiff, including Peter, only during his Pontificate. So if the Roman Pontiff resigns, he gives up not only the authority of the Roman Pontiff, but also the charisms that keep the authority from going astray. Similarly, when Christ changes the name of Simon to Peter, the Lord says, “upon this rock I will build my Church”, saying “I will build” indicates that this role of Peter is in the future. Then, as Pope Pius XII teaches in the document Mystical Body of Christ [n. 40, see below] Peter did not become the Roman Pontiff until the Ascension of Christ. For a Ruler does not need a Vicar while he is still present.

Pope Saint Nicholas I (the Great): “The privileges of this see are perpetual, divinely rooted and also planted. One can strike against them but not transfer them; one can drag them but not tear them out. Those matters which were formerly your domain remain, thanks be to God, insofar as they are inviolate; they will remain after you and so long as the Christian name will be preached, they will not cease to exist…. For among other things, these privileges are especially conferred through us, ‘You later being converted,’ he heard from the Lord, ‘confirm your brethren.’ [Lk 22:32] ” [Pope Saint Nicholas I, Letter to the Emperor Michael.]

~ Notice that Pope Saint Nicholas I explains this clearly in the way he chose to phrase the Gospel verse: “You later being converted”. And this conversion occurred initially, when he repented of his sin of betrayal; again, when he expressed his three-fold love for Christ and received the three-fold commission to feed His sheep; and finally, in its fullness, at the Ascension, when Christ rose up to Heaven, and Peter became the Roman Pontiff, with all the accompanying authority and charisms.

~ Then once a Roman Pontiff has these charisms, they are “perpetual”. So the never-failing faith charism, being perpetual, protects the Roman Pontiff from heresy and every other grave failure of faith (such as apostasy or idolatry) at all times during his Pontificate, and not only when he is teaching infallibly. Then the charism are also divinely planted and divinely rooted, and so cannot be torn out of any Roman Pontiff, whether he be a great Saint or a great sinner.

Saint Bernard: “It is fitting that every danger and scandal of the kingdom of God be referred to your Apostolate and especially these which touch upon the faith. For I regard it worthy that there, above all, dangers to the faith are mended, where one cannot think the faith is lacking. For to what other See was it ever said: ‘I have prayed for thee, that thy faith not fail?’ [Lk 22:32]” [Saint Bernard, Epist. 190 ad Innocentium, Letter to Pope Innocent]

Saint Cyril: “According to this promise of the Lord, the Apostolic Church of Peter remains pure and spotless from all leading into error, or heretical fraud, above all Heads and Bishops, and Primates of Churches and people, with its own Pontiffs, with most abundant faith, and the authority of Peter. And while other Churches have to blush for the error of some of their members, this [Apostolic Church of Peter] reigns alone, immovably established, enforcing silence, and stopping the mouths of all heretics; and we, from the necessity of salvation, not drunken with the wine of pride, confess, together with it, the formula of truth and of the holy apostolic tradition.” [Catena Aurea of St. Thomas on Mt 16:18]

Theodotus of Ancyra, martyr: “This holy See holds the reign of the Churches of the world, not only on account of other things, but also because she remains free from the heretical stench.” [Theodoret, Epistola ad Renatum Presbyterum Romanum]

~ The above three quotes support the papal charism of truth and never-failing faith, and the unblemished Apostolic See. They also repeat the teaching that excludes heresy from the See of Peter and his successors. Saint Bernard says that dangers to the faith must be mended only there, at the Apostolate of the Roman Pontiff, because there faith cannot be lacking — specifically because of the prayer of Christ in Luke 22:32. You will see this verse cited again and again, because the teaching of the ordinary universal Magisterium is that this verse means every Pope has the charism of never-failing faith. And this same teaching is also found in two Ecumenical Councils, in Vatican I and in Constantinople III.

~ Saint Cyril, in the so-called Golden Chain of Saint Thomas Aquinas (a commentary on the Gospels), says that the “Apostolic Church of Peter” has never had to blush for its errors, as other Churches have. For only the See of Peter can stop the mouths of all heretics, enforcing silence on those who err gravely. Then the martyr Theodotus says that the holy See of Peter has authority over all other Churches for many reasons, including that “She remains free from the heretical stench.” This teaching that the Apostolic See of the Roman Pontiff is always free from heresy accompanies the teaching that Luke 22:32 is to be understood as a charism given to every Roman Pontiff of truth and never-failing faith.

Pope Saint Boniface I (422): “there is to be no review of our judgment. In fact, it has never been licit to deliberate again on that which has once been decided by the Apostolic See.” [Pope Saint Boniface I, Letter to the Bishop of Thessalonica, Denzinger 422.]

Saint Augustine: “Roma locuta est; causa finita est [Rome has spoken; the case is closed].” [attributed to Augustine; actual source unknown. But it is a widely used and approved formula.]

Pope Saint Boniface I (418-422): “No one has ever boldly raised his hands against the Apostolic Eminence, from whose judgment it is not permissible to dissent; no one has rebelled against this, who did not wish judgment to be passed upon him.” [Pope Boniface I, Letter “Manet Beatum” to Rufus and the Other Bishops in Macedonia; March 11, 422; Denzinger n. 235.]

Pope Saint Nicholas I: “Since, according to the canons, where there is a greater authority, the judgment of the inferiors must be brought to it to be annulled or to be substantiated, certainly it is evident that the judgment of the Apostolic See, of whose authority there is none greater, is to be refused by no one….”
[Pope Saint Nicholas I, Letter Proposueramus quidem to Emperor Michael, 865; Denzinger n. 638-641.]

Canon 1404: “The First See is judged by no one.”
[Canon 1404; also taught by: Pope Saint Leo IX; Pope Boniface VIII, Unam Sanctam; Vatican I.]

~ And this freedom from grave error, especially freedom from heresy, this never-failing faith of Peter and his successors, is the reason that there can be no review of the decisions of the Apostolic See by anyone. Once the Roman Pontiff decides, the case is closed. And so Pope Saint Boniface says that it is not permissible to dissent from the judgment of the Roman Pontiff. He cannot teach heresy, or err gravely in faith or morals, not err gravely even in matters of discipline — otherwise the perennial teaching of the Church would not have issued a constant series of expressions calling the Apostolic See unsullied, unblemished, spotless, free from every contagion, free from heresy, etc. God would not have given the Roman Pontiff such supreme authority, which is without appeal and cannot be judged by anyone, without also giving the Roman Pontiff the charisms needed to keep him from grave errors that would lead to grave harm from any misuse of that authority. And these papal charisms, which accompany the papal authority, keep the Church indefectible.

Pope Saint Gelasius I, 492-496: “This is what the Apostolic See guards against with all her strength because the glorious confession of the Apostle is the root of the world, so that she is polluted by no crack of depravity and altogether no contagion. For if such a thing would ever occur (which may God forbid and we trust cannot be), why would we make bold to resist any error?” [Epistle to the Emperor Anastasius; quoted in: Bellarmine, Robert. On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) (p. 161). Mediatrix Press]

Pope Saint Gregory the Great, 590-604: “Who does not know that the whole Church was strengthened in the firmness of the Prince of the Apostles, to whom it was said, ‘Upon this rock I will build my Church … and thou, being converted, confirm thy brethren?’ [Mt 16:18; Lk 22:32]”

Saint Bellarmine: “There Gregory clearly teaches the strength of the Church depends upon the strength of Peter, and hence Peter is less able to err than the Church herself.” [Saint Gregory the great; quoted from the book: Bellarmine, Robert. On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) (p. 161). Mediatrix Press.]

~ Pope Saints Gelasius and Gregory teach that the Apostolic See has never been polluted by any crack of depravity, nor any contagion. For its teaching is the “root of the world” and the whole Church is strengthened by the firmness of Peter, the Rock on which the Church is founded. Then Doctor of the Church, Saint Robert Bellarmine draws from the teaching of Saint Gregory that “Peter is less able to err than the Church herself”, since Her indefectibility is established by means of his indefectibility. Thus, the gates of Hell cannot prevail over the Church, nor over the Roman Pontiff, for if the Rock fails, then the Church built upon that Rock would also fail.

Pope Pelagius II, 590 AD: “For you know how the Lord in the Gospel declares: ‘Simon, Simon, behold Satan has desired you that he might sift you as wheat, but I have prayed to the Father for thee, that thy faith fail not, and thou, being converted, confirm thy brethren.’ See, beloved, the truth cannot be falsified, nor can the faith of Peter ever be shaken or changed.” [Pope Pelagius II, writing to the Bishops of Istria, quoted in: Cardinal Manning, The Vatican Council and Its Definitions; p. 88.]

Saint Augustine: “For my part, I should not believe the Gospel except as moved by the authority of the Catholic Church.” [Willis, The Teachings of the Church Fathers, n. 171.]

Theodore the Studite: “I witness now before God and men, they [the Iconoclasts] have torn themselves away from the Body of Christ, from the Supreme See [Rome], in which Christ placed the keys of the faith, against which the gates of hell (I mean the mouths of heretics) have not prevailed, and never will until the Consummation, according to the promise of Him who cannot lie. Let the most blessed and apostolic [Pope] Paschal rejoice therefore, for he has fulfilled the work of Peter.” [PG 99:1281]

~ Saint Augustine requires the authority of the Church for his beliefs, and the highest authority is the Roman Pontiff. But Pope Pelagius II is more specific, it is the prayer of Jesus that the faith of Peter cannot fail that keeps every one of his successors so firm in faith that their faith is Peter’s faith, and their faith cannot be shaken or changed. As for Theodore, he teaches that the mouths of heretics (i.e. their errors spread by word) can never prevail over the Supreme See of Rome. For this is the promise of Jesus, who cannot lie. Thus, the never-failing faith of the Roman Pontiff, again, is understood as protecting the Pope from all heresy. And the gates of Hell cannot fail over he who holds the Keys of Saint Peter, which are called “the keys of the faith”. And this again implies that heretics and heresy cannot prevail over the Roman Pontiff.

Pope Saint Leo IX, Epistle to Peter of Antioch: “Without a doubt, it was for him alone, whom the Lord and Savior asserted that he prayed that his faith would not fail, saying, ‘I have prayed for thee, etc.’ [Lk 22:32]. Such a venerable and efficacious prayer has obtained that to this point the faith of Peter has not failed, nor can it be believed that it is ever going to fail in his throne.” [Bellarmine, Robert. On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) (p. 158). Mediatrix Press.]

Pope Saint Leo IX: “By the See of the Chief of the Apostles, namely by the Roman Church, through the same Peter, as well as through his successors, have not the comments of all the heretics been disapproved, rejected, and overcome, and the hearts of the brethren in the faith of Peter — which so far neither has failed, nor up to the end will fail — been strengthened?” [In Terra Pax Hominibus, September 2, 1053; Denz. 351.]

Pope Leo XIII:
“And since all Christians must be closely united in the communion of one immutable faith, Christ the Lord, in virtue of His prayers, obtained for Peter that in the fulfilment of his office he should never fall away from the faith. ‘But I have asked for thee that thy faith fail not’ [Luke 22:32], and He furthermore commanded him to impart light and strength to his brethren as often as the need should arise: ‘Confirm thy brethren’ [ibid.]. He willed then that he whom He had designated as the foundation of the Church should be the defense of its faith.” [Pope Leo XIII, Satis Cognitum 12.]

~ Above we have two Popes and three teachings, and all teach the same doctrine, that the faith of Peter and his successors cannot fail. Leo IX says first that the prayer of Jesus that the faith of Peter would not fail is so effective that the Lord obtained that no successor of Peter ever has failed in faith, and no successor of Peter ever will fail in faith. Then he phrases the same teaching differently, that the faith of Peter so far has not failed and will not fail even up to the end. And this never-failing faith gives the Roman Pontiffs the role to disapprove, reject, and overcome the words of the heretics. Finally, Pope Leo XIII teaches that Jesus obtained that Peter would never fall away from the faith, that he would confirm his brethren, the body of Bishops, so that their fail would never fail, as a body, and that the Roman Pontiff would be both the foundation of the Church and the defense of the Church’s faith.

~ So the never-failing faith of Peter and his successors implies freedom from heresy, and the role of judging heretics. For the Roman Pontiff is the only human person on earth who can be absolutely guaranteed to be free from heresy. The body of Bishops has the same gift to be free from heresy, but only as a body. So as far as we poor fallen sinners here on earth are concerned, the only individual fallen sinner who certainly is not a heretic is the Roman Pontiff; thus, he has the role to judge heretics.

Pope Leo XIII: “The meaning of this divine utterance [referencing Origen] is, that, notwithstanding the wiles and intrigues which they bring to bear against the Church, it can never be that the church committed to the care of Peter shall succumb or in any wise fail. ‘For the Church, as the edifice of Christ who has wisely built “His house upon a rock,” cannot be conquered by the gates of Hell, which may prevail over any man who shall be off the rock and outside the Church, but shall be powerless against it’ (Origenes, Comment. in Matt., tom. xii., n. ii). Therefore God confided His Church to Peter so that he might safely guard it with his unconquerable power.” [Pope Leo XIII, Satis Cognitum, n. 12]

Pope Leo XIII: “Union with the Roman See of Peter is to him [St. Jerome] always the public criterion of a Catholic. ‘I acknowledge everyone who is united with the See of Peter’ (Ep. xvi., ad Damasum, n. 2).”

“And for a like reason St. Augustine publicly attests that, ‘the primacy of the Apostolic chair always existed in the Roman Church’ (Ep. xliii., n. 7); and he denies that anyone who dissents from the Roman faith can be a Catholic. ‘You are not to be looked upon as holding the true Catholic faith if you do not teach that the faith of Rome is to be held’ (Sermo cxx., n. 13). So, too, St. Cyprian: ‘To be in communion with [Pope] Cornelius is to be in communion with the Catholic Church’ (Ep. lv., n. 1).” [Pope Leo XIII, Satis Cognitum, n. 13; citing Ss. Jerome, Augustine, Cyprian]

Pope Leo XIII:
“In the same way Maximus the Abbot teaches that obedience to the Roman Pontiff is the proof of the true faith and of legitimate communion. “Therefore if a man does not want to be, or to be called, a heretic, let him not strive to please this or that man…but let him hasten before all things to be in communion with the Roman See. If he be in communion with it, he should be acknowledged by all and everywhere as faithful and orthodox. He speaks in vain who tries to persuade me of the orthodoxy of those who, like himself, refuse obedience to his Holiness the Pope of the most holy Church of Rome: that is to the Apostolic See.”
[Pope Leo XIII, Satis Cognitum, n. 13; quoting St. Maximus the Abbot, Defloratio ex Epistola ad Petrum illustrem]

~ To avoid heresy, Pope Leo XIII teaches in the words of Saint Maximus, one must be in communion with the Roman See “before all things”. Those in that communion are “faithful and orthodox”. And this implies that the Roman Pontiff can never fail in orthodoxy, which means not only that the Pope has freedom from heresy, but also freedom from every grave error on doctrine and discipline. For if someone were to accept only the doctrines of the Church and not also Her disciplines, that is, if he were to accept only Her authority over the one Key and not the other, that person could not be said to be orthodox. Orthodoxy absolutely requires submission to the Roman Pontiff and the decisions of the Apostolic See on both doctrine and discipline.

Pope Saint Pius X, 1912: “The Pope is the guardian of dogma and morals; he is the depositary of the principles that form honest families, great nations, holy souls; he is the counselor of princes and peoples; it is the head under which no one feels tyrannized, because it represents God himself; he is the father par excellence who in himself brings together everything that can be loving, tender, divine. It seems incredible, and it is also painful, that there are priests to whom this recommendation should be made, but unfortunately we are in our days in this hard unhappy condition of having to say to priests: love the Pope!” [Pope Saint Pius X, Speech, 18 November 1912; Address of the Holy Father Pius X to the Priests of the Apostolic Union on the Occasion of the Fiftieth Anniversary of the Foundation]

~ It is a common mark of heretics, schismatics, apostates, idolaters, and others who reject the Church in one way or another, that they express malice toward the Roman Pontiff. Catholics who reject the teaching of the Church against contraception, often speak with malice or disdain or contempt about the Roman Pontiffs. Catholics who reject the decision of Pope Francis on the Latin Mass often speaks with malice toward him. The same is true for those who reject Vatican I or II, or who reject any definitive decision of the Apostolic See on doctrine or discipline. They have lost faith, or their faith is failing, and so they have lost the infused theological virtue of love, or it is failing. For no one can have love and hope without faith. So while love is the greatest of the three infused virtues, faith is the foundation of those virtues. When one sins against faith so gravely that faith is failing or has failed, love is also failing or has failed, and so malice, contempt, cruel words, hateful expressions and the like abound against the Roman Pontiff, who represents the Church that they have rejected by their loss of faith. Love the Pope, and obey him. Then you will have love, faith, and hope.

~ I see this mark again and again with the opponents of Pope Francis. They do not merely disagree or disobey, they pour out a seemingly unending series of malicious remarks at him. This lack of love for the Vicar of Christ shows a failing of faith in them. Even if they have not lost faith entirely, which necessarily implies a loss of love, hope, and the state of grace, the intensity of the virtues of love and hope decreases when faith itself is decreasing. As one is stumbling in faith, love grows lukewarm and can even be lost. The fullness of faith in the Tradition and Scripture and the Magisterium is necessary for love of the Lord Jesus to grow strong in us.

Pius X: “The office divinely committed to Us of feeding the Lord’s flock has especially this duty assigned to it by Christ, namely, to guard with the greatest vigilance the deposit of the faith delivered to the saints, rejecting the profane novelties of words and oppositions of knowledge falsely so called. There has never been a time when this watchfulness of the supreme pastor was not necessary to the Catholic body….” [Pope Saint Pius X, Pascendi Dominici Gregis, n. 1]

Pius X: “Therefore when one loves the Pope, there is no discussion about what he disposes or demands, or how far obedience must go, and in what things one must obey; when one loves the Pope, one does not say that he did not speak clearly enough, as if he were obliged to repeat in the ear of everyone that clearly expressed will many times, not only verbally, but with letters and other public documents…”
[Pope Saint Pius X, Speech, 18 November 1912.]

Pius X: “…his orders are not questioned, citing the easy pretext of those who do not want to obey, that it is not the Pope who commands, but those who surround him; the field in which he can and must exercise his authority is not limited; The authority of the Pope is not preceded by that of other people, however learned, who disagree with the Pope, who, if they are learned, are not saints, because whoever is holy cannot disagree with the Pope.” [Pope Saint Pius X, Speech, 18 November 1912.]

~ It is so often said that those clergy or theologians who are disagreeing with the Pope should be followed instead of him, because they are supposedly learned and holy. But Pope Saint Pius X teaches that those who disagree with the Pope, no matter how learned they may be, “are not saints, because whoever is holy cannot disagree with the Pope.” So the alleged wisdom and holiness of those who reject the decisions of the Pope on doctrine or discipline is no excuse. We must follow the teachings of the Magisterium, even if some of the Saints, who lived before those magisterial decisions were made, happened to disagree.

Pope Pius XI, 1933: “without the Shepherd, little sheep would go astray and more easily become the prey of false shepherds…. more than the help of men, We must have confidence in the indefectible assistance promised by God to His Church and in the immense goodness of the Lord toward those who love Him.” [Pope Pius XI, Dilectissima Nobis, n. 18, 26.]

Pope Pius XI: “Wherefore, let the faithful also be on their guard against the overrated independence of private judgment and that false autonomy of human reason. For it is quite foreign to everyone bearing the name of a Christian to trust his own mental powers with such pride as to agree only with those things which he can examine from their inner nature, and to imagine that the Church, sent by God to teach and guide all nations, is not conversant with present affairs and circumstances; or even that they must obey only in those matters which she has decreed by solemn definition as though her other decisions might be presumed to be false or putting forward insufficient motive for truth and honesty. Quite to the contrary, a characteristic of all true followers of Christ, lettered or unlettered, is to suffer themselves to be guided and led in all things that touch upon faith or morals by the Holy Church of God through its Supreme Pastor the Roman Pontiff, who is himself guided by Jesus Christ Our Lord.” [Pope Pius XI, Casti Connubii, 104.]

~ The sheep need the guidance of the chief Shepherd, the Vicar of Christ, no matter how learned or holy they might be (or seem to be in their own eyes). For the assistance promised to Peter and his successors is indefectible. And that is how the Church remains indefectible, by the indefectible assistance given to the Roman Pontiffs by God for the sake of His Church. The never-failing faith of the Roman Pontiff is part of this indefectible assistance he receives from Christ for the sake of the Church.

~ Those who oppose the Roman Pontiffs or the Ecumenical Councils make the same mistake, putting private judgment and human reason above faith in the authority of the Church. Faith rests on authority, not on having the best theological argument or the most supporters. We must trust the Church over our own “mental powers”. For trusting in one’s own judgment is nothing but pride. And it is also a similar grave error to accept only the infallible teachings of the Magisterium, and then to subject every non-infallible decision to one’s own private judgment. Instead, all the decisions of the Roman Pontiff and the body of Bishops and the Ecumenical Councils require either the full assent of faith or religious submission of mind and will. Read this again: “a characteristic of all true followers of Christ, lettered or unlettered, is to suffer themselves to be guided and led in all things that touch upon faith or morals by the Holy Church of God through its Supreme Pastor the Roman Pontiff, who is himself guided by Jesus Christ Our Lord.” Now obey it. The licit theological dissent that is possible in regard to a non-infallible decision of doctrine or discipline should be uncommon, if not rare. If it is common, you are in grave error.

Cardinal Ratzinger: “But it would be contrary to the truth, if, proceeding from some particular cases, one were to conclude that the Church’s Magisterium can be habitually mistaken in its prudential judgments, or that it does not enjoy divine assistance in the integral exercise of its mission.” [Cardinal Ratzinger, CDF, Donum Veritatis, 24.]

Pope Pius XII, 1943: “But we must not think that He rules only in a hidden or extraordinary manner. On the contrary, our Redeemer also governs His Mystical Body in a visible and normal way through His Vicar on earth. You know, Venerable Brethren, that after He had ruled the ‘little flock’ Himself during His mortal pilgrimage, Christ our Lord, when about to leave this world and return to the Father, entrusted to the Chief of the Apostles the visible government of the entire community He had founded. Since He was all wise He could not leave the body of the Church He had founded as a human society without a visible head. Nor against this may one argue that the primacy of jurisdiction established in the Church gives such a Mystical Body two heads. For Peter in view of his primacy is only Christ’s Vicar; so that there is only one chief Head of this Body, namely Christ, who never ceases Himself to guide the Church invisibly, though at the same time He rules it visibly, through him who is His representative on earth. After His glorious Ascension into Heaven this Church rested not on Him alone, but on Peter, too, its visible foundation stone. That Christ and His Vicar constitute one only Head is the solemn teaching of Our predecessor of immortal memory Boniface VIII in the Apostolic Letter Unam Sanctam; and his successors have never ceased to repeat the same.”

“They, therefore, walk in the path of dangerous error who believe that they can accept Christ as the Head of the Church, while not adhering loyally to His Vicar on earth. They have taken away the visible head, broken the visible bonds of unity and left the Mystical Body of the Redeemer so obscured and so maimed, that those who are seeking the haven of eternal salvation can neither see it nor find it.” [Pope Pius XII, Mystici Corporis Christi, n. 40-41.]

~ Christ and His Vicar constitute one only Head of the one Church. That is an infallible teaching of the Magisterium, for it was taught by Unam Sanctam, which was approved by the Fifth Lateran Council, and was taught continually by the successors of Pope Boniface VIII. Any Catholic who rejects the Roman Pontiff, rejects Christ. For the two are one Head of the one Church. And from this unity flows the papal charisms, from Christ to the Roman Pontiff, charisms that keep the decisions of the Roman Pontiff from grave error, and keep him also from ever failing in faith.

Pope Benedict XV: “The ancient Fathers, especially those who held the more illustrious chairs of the East, since they accepted these privileges as proper to the pontifical authority, took refuge in the Apostolic See whenever heresy or internal strife troubled them. For it alone promised safety in extreme crises. Basil the Great did so, as did the renowned defender of the Nicene Creed, Athanasius, as well as John Chrysostom. For these inspired Fathers of the orthodox faith appealed from the councils of bishops to the supreme judgement of the Roman Pontiffs according to the prescriptions of the ecclesiastical Canons.” [Pope Benedict XV, Principi Apostolorum Petro, n. 3.]

Pope Saint Paul VI, 1968: “founded upon the Apostles and handing on from century to century their ever-living Word and their powers as Pastors in the successor of Peter and the bishops in communion with him; perpetually assisted by the Holy Spirit, She has the charge of guarding, teaching, explaining and spreading the Truth which God revealed in a then-veiled manner by the prophets, and fully by the Lord Jesus.” [Pope Saint Paul VI, Apostolic Letter Solemni Hac Liturgia]

~ The Pope is perpetually assisted by the Holy Spirit, as are the body of Bishops, if the remain in communion with and in obedience to the Pope. Hence, the Pope and the body of Bishops with him have the assistance of God in all their decisions, though some errors are possible in what is non-infallible. Notice that the Fathers of the Church and the highest authorities in the East “took refuge in the Apostolic See whenever heresy” or strife troubled them. Again, the Roman Pontiff is the bulwark against heresy, because of his never-failing faith. And this never-failing faith and freedom from heresy is due to the assistance of the Holy Spirit and the union of Christ with His Vicar as one only Head of the one Church.

Saint John Henry Newman: “I have said that, like St. Peter, he is the Vicar of his Lord. He can judge, and he can acquit; he can pardon, and he can condemn; he can command and he can permit; he can forbid, and he can punish. He has a Supreme jurisdiction over the people of God. He can stop the ordinary course of sacramental mercies; he can excommunicate from the ordinary grace of redemption; and he can remove again the ban which he has inflicted. It is the rule of Christ’s providence, that what His Vicar does in severity or in mercy upon earth, He Himself confirms in heaven.

“in his administration of Christ’s kingdom, in his religious acts, we must never oppose his will, or dispute his word, or criticize his policy, or shrink from his side… We must never suffer ourselves to doubt, that, in his government of the Church, he is guided by an intelligence more than human. His yoke is the yoke of Christ, he has the responsibility of his own acts, not we; and to his Lord must he render account, not to us. Even in secular matters it is ever safe to be on his side, dangerous to be on the side of his enemies.” [St. John Henry Newman, The Pope and the Revolution, Sermons Preached on Various Occasions, Sermon 15]

~ Never treat the Roman Pontiff as if he were speaking and acting merely from his own human mind and heart. That is a very grave error against the teachings of Christ in the Gospels, especially (Mt 16:18; Lk 22:32). And if you think that a Pope can be deposed because his teaching does not agree with your understanding, read what Saint Newman says again. Whatever the Vicar of Christ decides on earth is confirmed in Heaven.

Pope Saint John Paul II: “This is Christ’s promise, our consoling certainty: the Petrine ministry is not founded on human abilities and strengths, but on the prayer of Christ who implores the Father that Simon’s faith ‘may not fail’ (Lk 22:32).” [Pope Saint John Paul II, 22 February 2000, Homily of the Holy Father]

Pope John Paul II: “The assistance that Christ promised to Peter also accompanies his successors, who are entrusted with the same task for the Church: ‘I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren’ (Lk 22:32). So Peter becomes the ‘rock’ on which Christ can build his Church in history, by a gift from on high: the gift of faith, solemnly confessed at Caesarea Philippi: ‘You are the Christ, the Son of the living God’ (Mt 16:16). But it is also in virtue of his response of singular love that he is chosen to be the foundation of the Church: ‘Simon, son of John, do you love me more than these?… Lord, you know everything; you know that I love you’ (cf. Jn 21:15-19). On the rock of this faith and this love, the Lord holds together his mystical Body and assures the permanent unity and mission in the varied events of history.” [Pope John Paul II, Address to the Associations of Saints Peter and Paul, 16 June 2001]

~ And above we have one of the most recent assertions of the teaching of the ordinary universal Magisterium and of Constantinople III and Vatican I on the never-failing faith of Peter and his successors, this time expressed by Pope Saint John Paul II. How much clearer could a teaching of the Magisterium be?

~ Let’s return now to some further insights from Vatican I, the fathers of that Council, and Saint Robert Bellarmine, whose work was adopted by the Council.

Bishop Vincent Gasser, a father of Vatican I: “But if the Pontiff should fall into an error of faith, the Church would dissolve, deprived of the bond of unity.” [Bishop Vincent Ferrer Gasser, deputation from Pope Pius IV, Relatio to Vatican I, n. 7-8]

Bishop Auguste Allou of Meaux, a father of Vatican I: “If this Roman See could fall and be no longer the See of truth but of error and pestilence, then the Catholic Church herself would not have the bond of a society and would be schismatic and scattered — which in fact is impossible.” [The Bishop of Meaux, French Bishop Auguste Allou, a father of Vatican I, quoted in the Relatio of Vatican I by Bishop Gasser]

Cardinal Manning, 1870: “The application of the promise ‘Ego rogavi pro te,’ [“I have prayed for you”] etc. to the infallible faith of Peter and his successors, is made by St. Ambrose; St. Augustine; St. Leo; St. Gelasius; Pelagius II; St. Gregory the Great; Stephen, Bishop of Dori in a Lateran Council [of 649, not Ecumenical]; St. Vitalian; the Bishops of the IV Ecumenical Council AD 451 [Chalcedon]; St. Agatho in the VI AD 680 [Constantinople III]; St. Bernard AD 1153; St. Thomas Aquinas AD 1274; St. Bonaventure AD 1274; that is, this interpretation is given by three out of the four Doctors of the Church, by six Pontiffs down to the seventh century. It was recognized in two Ecumenical Councils. It is expressly declared by the Angelic Doctor, who may be taken as the exponent of the Dominican school, and by the Seraphic Doctor, who is likewise the witness of the Franciscan; and by a multitude of Saints.” [Cardinal Manning, “The Vatican Council and Its Definitions: A Pastoral Letter to the Clergy”, p. 83-84.]

Cardinal Manning: “The interpretation by the Fathers of the words ‘On this rock,’ etc. is fourfold, but all four interpretations are not more than four aspects of one and the same truth, and all are necessary to complete its full meaning. They all implicitly or explicitly contain the perpetual stability of Peter’s faith….”

Cardinal Manning: “In these two promises [Lk 22:32, Mt 16:18] a divine assistance is pledged to Peter and to his successors, and that divine assistance is promised to secure the stability and indefectibility of the Faith in the supreme Doctor and Head of the Church, for the general good of the Church itself.” [Cardinal Manning, “The Vatican Council and Its Definitions: A Pastoral Letter to the Clergy”]

Saint Robert Bellarmine: “The Pope is the Teacher and Shepherd of the whole Church, thus, the whole Church is so bound to hear and follow him that if he would err, the whole Church would err.” [On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) p. 162 Mediatrix Press]

~ The Church is indefectible. She cannot go astray or lead astray. She cannot teach grave error on doctrine, nor err gravely on discipline. And since the Roman Pontiff is the Rock on which the Church is founded, and the Head of the Church, the Roman Pontiff also is indefectible.

Bellarmine: “Now our adversaries respond that the Church ought to hear him [the Roman Pontiff] so long as he teaches correctly, for God must be heard more than men. On the other hand, who will judge whether the Pope has taught rightly or not? For it is not for the sheep to judge whether the shepherd wanders off, not even and especially in those matters which are truly doubtful. Nor do Christian sheep have any greater judge or teacher to whom they might have recourse. As we showed above, from the whole Church one can appeal to the Pope; yet from him no one is able to appeal; therefore necessarily the whole Church will err, if the Pontiff would err.” [Ibid.]

Bellarmine, on Lk 22:32: “Therefore, the true exposition is that the Lord asked for two privileges for Peter…. The second privilege is that he, as the Pope, could never teach something against the faith, or that there would never be found one in his See who would teach against the true faith. From these privileges, we see that the first did not remain to his successors, but the second without a doubt did.” [Ibid. 156]

Saint Robert Bellarmine, Book 4, Chapter VI, referenced by Bishop Gasser in the Relatio of Vatican I:
“THE FOURTH proposition. It is probable and may piously be believed that not only as Pope can the Supreme Pontiff not err, but he cannot be a heretic even as a particular person by pertinaciously believing something false against the faith. It is proved:
1) because it seems to require the sweet disposition of the providence of God. For the Pope not only should not, but cannot preach heresy, but rather should always preach the truth. He will certainly do that, since the Lord commanded him to confirm his brethren, and for that reason added: ‘I have prayed for thee, that thy faith shall not fail,’ [Lk 22:32] that is, that at least the preaching of the true faith shall not fail in thy throne.”

“How, I ask, will a heretical Pope confirm the brethren in faith and always preach the true faith? Certainly God can wrench the confession of the true faith out of the heart of a heretic just as he placed the words in the mouth of Balaam’s ass. Still, this will be a great violence, and not in keeping with the providence of God that sweetly disposes all things.”

“2) It is proved ab eventu. For to this point no [Pontiff] has been a heretic, or certainly it cannot be proven that any of them were heretics; therefore it is a sign that such a thing cannot be.”
[Bellarmine, Robert. On the Roman Pontiff, vol. 2: Books III-V (De Controversiis) (p. 171). Mediatrix Press. Kindle Edition.]

~ When Saint Robert Bellarmine says that as Pope, the Supreme Pontiff cannot err, he means not err gravely. So he cannot fall into even material heresy. Then as a private person, he also cannot commit formal heresy or in any way be a heretic. And this is the position that Bishop Gasser, in the Relatio of Vatican I, explained to the Council fathers that they would be raising to the dignity of a dogma if they voted for the fourth chapter of Pastor Aeternus (which they did). So the charism of truth and of never-failing faith certainly includes freedom from material and formal heresy in the Roman Pontiff at all times.

Canon 331: “The bishop of the Roman Church, in whom continues the office given by the Lord uniquely to Peter, the first of the Apostles, and to be transmitted to his successors, is the head of the college of bishops, the Vicar of Christ, and the pastor of the universal Church on earth. By virtue of his office he possesses supreme, full, immediate, and universal ordinary power in the Church, which he is always able to exercise freely.” [Code of Canon Law, 1983: Canon 331]

Summary

The Ecumenical Councils and the Roman Pontiffs, and the Saints all teach the same related set of teachings:
1. that every Roman Pontiff has the charism of truth and of never-failing faith
2. that no Roman Pontiff can teach or commit heresy
3. that the Apostolic See is always free from grave errors on doctrine and discipline
4. that the Roman Pontiff has supreme power, without possibility of appeal, and is judged by God alone
5. that the indefectibility of the Church depends upon the indefectibility of the Roman Pontiffs
6. that Christ and His Vicar constitute one only Head of the one Church
7. that orthodoxy depends upon communion with the Roman Pontiff and the Apostolic See

Ronald L. Conte Jr.