Gregory Palamas:
The first traitor, who incited the first man to desert God, saw Him Who had earlier made Adam, the father of the human race, later re-creating Peter as the father of all true worshippers.
He not only saw, but also heard the Creator saying to Peter: “Thou art Peter, and upon this rock I will build my church” (Matt. 16:18).
Once the prince of evil found this out…, he tempted Peter, the first leader of God’s faithful people, as he had previously tempted Adam, the founder of the race of men.
Realizing that Peter was endowed with intelligence and afire with love for Christ, he did not dare make a direct attack.
Instead he came upon him from the right flank, cunningly deceiving him into being excessively eager.
At the time of the saving Passion, when the Lord told His disciples, “All ye shall be offended because of me this night” (Matt. 26:31), Peter disobediently contradicted Him.
He also exalted himself above the others, saying that even if everyone else were offended, he would not be (Matt. 26:33).
Because he had been beguiled into arrogance, he fell further than the rest, so that by humbling himself more than them he might eventually appear more radiant.
Unlike Adam who was tempted, vanquished and completely brought down, Peter, having been tempted and led astray a little, overcame the tempter.
How? Through his immediate condemnation of himself, his intense sorrow and repentance, and the medicine which brings forgiveness, tears.
“A broken and contrite heart”, it says, “O God, thou wilt not despise” (Ps. 51:17), and “Godly sorrow worketh repentance to salvation not to be repented of” (2 Cor. 7:10), and “They that sow their supplications in tears shall joyfully reap forgiveness” (cf. Ps. 126:5).
Anyone who looks at Peter will see that through repentance and painful grief he not only adequately healed the denial into which he had been drawn, but he also completely rooted out of his soul that passion which had made him fall behind the others.
Wishing to demonstrate this to everyone, the Lord, after His Passion in the flesh for our sake and His rising on the third day, used those words to Peter which we read in today’s Gospel, asking him, “Simon, son of Jonah, lovest thou me more than these” (John 21:15), meaning, “more than these disciples of mine”.
But see how much humbler he has become. Whereas before, even without being asked, he set himself above the rest and said that even if all forsook the Lord, he would not; now, on being asked whether he loves Him more than the others do, he affirms that he loves Him, but leaves out the word “more”, saying “Yea, Lord; thou knowest that I love thee” (John 21:15, 16, cf. 17).
Paul…was put to death every day, or rather he was always dead, no longer alive himself, as he tells us, but having Christ living in him (Gal. 2:20).
[...] He had zeal for God, and was jealous over us with divine jealousy (2 Cor. 11:2).
The only one to equal him in this was Peter, but hear how humble he is when he says of himself, “I am the least of the Apostles, that am not meet to be called an Apostle” (1 Cor. 15:9).
Given that Paul made the same confession of faith as Peter, and had the same zeal, humility and love, surely they received the same rewards.
[...] That is why the Lord told Peter, “Thou art Peter and upon this rock I will build my church” (Matt. 16:18), whereas He said to Ananias of Paul, “He is a chosen vessel unto me, to bear my name before the Gentiles and kings” (Acts 9:15).
Which name? Clearly the name we have been given, the name of Christ’s Church, which rests on the foundation stone of Peter.
Notice that Peter and Paul are equal in prominence and glory, and both hold up the Church. Consequently the Church now bestows one and the same honour on both, and celebrates them together with equal esteem.
As we consider the outcome of their lives, let us imitate how they lived, or at least how they were restored through humility and repentance, even if we cannot attain to their other great and exalted achievements, which are appropriate to great men and fitting for great men to emulate.
[...] Amendment through repentance, however, is more appropriate for us than for the great, since we all sin many times every day, and unless we lay hold of salvation through continuous repentance, we have no hope of it from any other source.
Repentance is preceded by awareness of our sins, which is a strong incentive to mercy. “Have mercy upon me”, said the Psalmist and Prophet to God, “for I acknowledge my transgressions” (Ps. 5 1:1, 3).
Through his recognition of sin he attracted God’s compassion, and through his confession and self-condemnation he obtained complete forgiveness.
“I said”, the Psalmist tells us, “I will confess my transgressions unto the Lord; and thou forgavest the iniquity of my heart” (cf. Ps. 32:5), because acknowledgment of our sins is followed by condemnation of ourselves, which in turn is followed by that sorrow for our sins which Paul calls “godly sorrow” (2 Cor. 7:10).
After godly sorrow confession and prayer to God with a contrite heart come naturally (Ps. 51:17), as does the promise to keep away from evil from now on. This is repentance.
Gregory Palamas (1296-1359): Homily on the Feast of St Peter and St Paul, 5-6 @Mystagogy.