God is One. There cannot be many Gods for the following reason. Suppose a theological belief that there are several Gods. The first God is not only perfect, but infinitely perfect, lacking in absolutely nothing, and existing unbounded by time and place. So what would a second God be like? He could not be the same as the first, but in a different place, or a different time, for any God by His Nature must be unlimited by time and place. A second God cannot be distinguished from the first God by being more perfect, or less perfect. A second God cannot be distinguished from the first God by having different qualities, since any God must be infinitely perfect in all that is Good; He must be Goodness Itself. There is nothing left for the Nature of the second God. So not only can there not be many Gods, there cannot be more than one God.

To explain this again by an analogy: suppose that there are several very wealthy men on earth, and to simplify, let’s say that wealth is measured only by ownership of land. There could be many very wealthy men, each owning vast expanses of land. But suppose we instead postulate several wealthy men, each of which is perfect and complete in all wealth. The first wealthy man will own the entire earth (since we are measuring wealth in this example by ownership of land). But there will be no more land left for a second man to be perfect and complete in wealth. So there can be only one.

Similarly, God is perfect and complete and infinite in His Nature; He is infinite Goodness. So there is nothing left for a second God to be.

Thus, the Three Persons of the One God do not each have His own perfect infinite Nature; the Nature of God is One. And the Nature is not shared in the sense of each Person possessing only part — each possesses the entire Whole of the Nature, without any detriment or loss or compromise to the possession of the other Persons of the same Nature.

But this poses a problem. What distinguishes the three Persons? There cannot be more than one infinitely perfect God, so the Nature is One. And God is ‘truly and absolutely simple’ (as both Augustine and Aquinas taught). So the one Nature is not divided into three parts. The Three Persons are distinct, yet each is perfect God, having the one and same Divine Nature.

The only basis for distinction between the Persons is procession.

The Father does not proceed.
The Son proceeds only from the Father.
The Spirit proceeds from the Father and the Son.

This distinction allows there to be Three Persons who are truly distinct from one another.

But if the Spirit proceeds only from the Father, just as the Son does, then there would be no distinction at all between Son and Spirit. For each is infinitely perfect God.

Therefore, the belief that the Spirit proceeds from the Father and the Son (in Latin: filioque) is essential to a proper understanding of the Three distinct Persons of the One Divine Nature. The Eastern Orthodox belief that the Son and the Spirit each proceed only from the Father results in no basis at all for the distinction between these Two Persons.

Biblical Basis

The Son proceeds from the Father. The Father does not proceed. Therefore, the Son does not send the Father to the world to be incarnate. Rather, the Father sends the Son into the world to be incarnate. It is fitting that the Father send the Son because the Father also ‘sends’ the Son in the sense of procession.

The Spirit is sent by the Father and by the Son. This is fitting because the Spirit proceeds from the Father and from the Son. If the Spirit proceeded only from the Father, then only the Father could send the Spirit.

[John]
{14:16} And I will ask the Father, and he will give another Advocate to you, so that he may abide with you for eternity:

{14:26} But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will suggest to you everything whatsoever that I have said to you.

{15:26} But when the Advocate has arrived, whom I will send to you from the Father, the Spirit of truth who proceeds from the Father, he will offer testimony about me.

[Luke]
{24:49} And I am sending the Promise of my Father upon you. But you must stay in the city, until such time as you are clothed with power from on high.”

The above verses portray the Spirit as being sent by the Father, at the request, or in the name, of the Son. Even the verse that says the Spirit proceeds from the Father, adds that the Spirit is sent by the Son and offers testimony about the Son, thereby implying procession also from the Son. But a Person of the Trinity could not be sent and offer testimony about the Son unless he proceeds also from the Son. Just as it would not be fitting for the Son or the Spirit to send the Father, so also it would not be fitting for the Spirit to be sent by the Son, to offer testimony about the Son, to teach and remind about the Son’s teachings, unless the Spirit also proceeded from the Son.

As it is with sending, so also with teaching.

[John]
{5:19} Then Jesus responded and said to them: “Amen, amen, I say to you, the Son is not able to do anything of himself, but only what he has seen the Father doing. For whatever he does, even this does the Son do, similarly.

{16:13} But when the Spirit of truth has arrived, he will teach the whole truth to you. For he will not be speaking from himself. Instead, whatever he will hear, he will speak. And he will announce to you the things that are to come.
{16:14} He shall glorify me. For he will receive from what is mine, and he will announce it to you.
{16:15} All things whatsoever that the Father has are mine. For this reason, I said that he will receive from what is mine and that he will announce it to you.

The Son only teaches what he learns from the Father, for the Son proceeds only from the Father. But the Spirit of truth teaches from the Father and from the Son, therefore he proceeds from the Father and from the Son. Otherwise, the Spirit could not receive from what is Jesus’. For each Person, as God, is infinite and perfect, in need of the reception of nothing. And so this reception from Jesus can only refer to procession.

Two Types of Procession

Although many sources use a different word to describe the procession of the Spirit as compared to the procession of the Son, the only real distinction between these two processions is that the Spirit proceeds from Two Persons (but in one act, i.e. as from one principle), and the Son proceeds only from One Person. The mere use of a different word to describe the procession of the Son and the procession of the Spirit does not, by itself, result in any real distinction. The Son has everything that he is from the Father — they are identical except that the Son depends upon the Father, by virtue of procession, for all that he is. If the Spirit has everything that he is from the Father also, then the Son and the Spirit would be identical. There would be literally nothing different between them, because each is perfectly infinite and infinitely perfect. Only if the Spirit proceeds from the Father and the Son, a double procession but as from one principle, is there a real basis for the distinction of the Third Person from the Second Person.

The Father does not proceed, therefore He is the first Person. The Son proceeds only from the Father, therefore He is the second Person. The Spirit proceeds primarily from the First Person and secondarily from the Second Person, but in one Act, therefore He is the third Person. If the Spirit proceeded only from the Father, then He would not be Third, but also Second (which is absurd). There is a distinction, within the double procession of the Spirit, between the role of the Father and the role of the Son in that one Act. This distinction is based on the fact that the Father does not proceed, but the Son does proceed. So the Spirit proceeds primarily from the Father and secondarily from the Son.

Heresy and Schism

The universal Church is of Rome. The Greek Churches are heretical and schismatic, as evidenced by their departure from the worldwide body of Bishops, their rejection of numerous successive Ecumenical Councils, and their rejection of the authority of numerous successive Popes. Peter was appointed directly by Christ to lead the Apostles, and Peter was the Bishop of Rome. The rejection of papal authority is an objective mortal sin. Several Eastern Churches have remained faithful to Rome, believing and teaching all that the Ecumenical Councils and the Popes and the body of Bishops also teach. They are witnesses against the heretical and schismatic Churches of the East, who reject the authority of Rome.

by
Ronald L. Conte Jr.
Roman Catholic theologian and
translator of the Catholic Public Domain Version of the Bible.