Jesus received authority to forgive sins as a man from the Father for He says “all authority has been given to Me” (Matt 28:18), and He then sends His Apostles with that same authority, He says “As the Father has sent me, I am sending you.” (John 20:21). Now, notice that after Jesus heals and forgives the sins of a paralytic man, the crowd praised God how He has given such authority to men (Matt 9:8). This “to men” is plural. There are some English translations that says “to a man”, but compared with the rest of the translations in the world we learn that it should be “to men”. So we clearly see here that God has given authority to men to forgive sins. But obviously, it’s not any men, but only those who have received such authority from Jesus and then it has been passed on through Apostolic Succession. No man can auto declare himself to have such authority.
Only God can forgive sins, this is true, that’s why some teachers of the O.T. law were shocked when Jesus (“a man”) started to forgive sins (Matthew 9:3). But what they ignored is that God became man (John 1:1) (1:14). The Father sent His Son for a mission, a ministry, and one of the things was to forgive sins ‘as a man’, talking to the other, that’s why we see Jesus, God made man, forgiving sins as in the case with the paralytic (Matt 9:1-7), or the woman caught in adultery (John 8:10-11). Now, since He was going to leave this world in His humanity, He did not want this act of mercy of a man forgiving sins to stop, He wanted this act of mercy to continue from generations to generations (Matthew 28:20), that’s why He said to His Apostles:
“Again Jesus said, “Peace be with you! *As the Father has sent me, I am sending you*.” And with that he breathed on them and said, “Receive the Holy Spirit. If you forgive anyone’s sins, their sins are forgiven; if you do not forgive them, they are not forgiven.” (John 20:21-23 – NIV).
It was Jesus Himself who passed on to them this authority through His breathing. Then St. Paul confirms this teaching:
“All this is from God, who reconciled us to himself through Christ and gave us the ministry of reconciliation: that God was reconciling the world to himself in Christ, not counting people’s sins against them. And he has committed to us the message of reconciliation. We are therefore Christ’s ambassadors, as though God were making his appeal through us. We implore you on Christ’s behalf: Be reconciled to God” – (2 Corinthians 5:18-20).
“Ambassadors” means representatives of someone else, and here St. Paul is referring to himself and Timothy (2 Cor 1:1).
It is Jesus who continues to forgive sins through His priests, the priests are only Jesus’ instruments. The efficacy of the priestly ministry does not depend upon the holiness of the priests. Of course, all priests are called to holiness, but the priest’s role is to be an instrument of Christ. Christ is the One who performs the Sacraments.
“For the law appoints as high priests men in all their weakness; but the oath, which came after the law, appointed the Son, who has been made perfect forever.” (Hebrews 7:28).
Priests are weak and with infirmities, like all of us, but Jesus, who is perfect, calls them for this particular especial service of the ordained priesthood of the new covenant (Luke 22:19-20) (Heb 7:12) for the benefit of us all.