Matthew 16:18

But in this bestowing of a new name is a happy foundation of the Church, and a rock worthy of that building, which should break up the laws of hell, burst the gates of Tartarus, and all the shackles of death. And to show the firmness of this Church thus built upon a rock, He adds, And the gates of hell shall not prevail against it.

What then saith Christ? "Thou art Simon, the son of Jonas; thou shalt be called Cephas." "Thus since thou hast proclaimed my Father, I too name him that begat thee;" all but saying, "As thou art son of Jonas, even so am I of my Father." Else it were superfluous to say, "Thou art Son of Jonas;" but since he had said, "Son of God," to point out that He is so Son of God, as the other son of Jonas, of the same substance with Him that begat Him, therefore He added this, "And I say unto thee, Thou art Peter, and upon this rock will I build my Church;" that is, on the faith of his confession. Hereby He signifies that many were now on the point of believing, and raises his spirit, and makes him a shepherd. "And the gates of hell shall not prevail against it." "And if not against it, much more not against me. So be not troubled because thou art shortly to hear that I shall be betrayed and crucified."

As much as to say, You have said to me, Thou art Christ, the Son of the living God, therefore I say unto thee, not in a mere speech, and that goes not on into operation; but I say unto thee, and for Me to speak is to make it sor, that thou art Peter. For as from Christ proceeded that light to the Apostles, whereby they were called the light of the world, and those other names which were imposed upon them by the Lord, so upon Simon who believed in Christ the Rock, He bestowed the name of Peter (Rock.) And pursuing the metaphor of the rock, it is rightly said to him as follows: And upon this rock I will build my Church. I suppose the gates of hell to mean vice and sin, or at least the doctrines of heretics by which men are ensnared and drawn into hell. Let none think that this is said of death, implying that the Apostles should not be subject to the condition of death, when we see their martyrdoms so illustrious.

(de Cons. Ev. ii. 53.) But let none suppose that Peter received that name here; he received it at no other time than where John relates that it was said unto him, Thou shalt be called Cephas, which is interpreted, Peter. (John 1:42.) (Retract. i. 21.) I have said in a certain place of the Apostle Peter, that it was on him, as on a rock, that the Church was built. But I know that since that I have often explained these words of the Lord, Thou art Peter, and on this rock will I build my Church, as meaning upon Him whom Peter had confessed in the words, Thou art Christ, the Son of the living God; and so that Peter, taking his name from this rock, would represent the Church, which is built upon this rock. For it is not said to him, Thou art the rock, but, Thou art Peter. (1 Cor. 10:4.) But the rock was Christ, whom because Simon thus confessed, as the whole Church confesses Him, he was named Peter. Let the reader choose whether of these two opinions seems to him the more probable.

CYRIL OF ALEXANDRIA.s; 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 reigns alone immoveably established, enforcing silence, and stopping the mouths of all heretics; and wet, not drunken with the wine of pride, confess together with it the type of truth, and of the holy apostolic tradition.