Christ spoke in the Gospel to St. Peter: "Thou art Peter, and upon this Rock I will build my church." On these words St. Augustine says, in his Sermons on the Words of the Lord, 13 [Nic. Fathers, 6: 340]: "Our Lord Jesus Christ thus spake to Peter, Thou art Peter and upon this rock I will build my church—on this Rock, which thou hast confessed, on this Rock which thou hast recognized, when thou saidst, 'Thou art Christ, the Son of the living God'—'I will build my church': I will build thee upon myself, not myself upon thee. For wishing that men should be built upon men, they were saying, 'I am of Paul, I of Apollos, and I of Cephas,' that is, Peter. And others who did not wish to be built upon Peter—Petrum—but upon the Rock—Petram—said, 'I am of Christ.' Again, in his last Homily on John [Nic. Fathers, 7: 450], Augustine says: "Peter the apostle, because of the primacy of his apostleship, had a symbolic and representative personality, for what belonged to him as an individual was that by nature he was one man, by grace one Christian, and by a more abundant grace he was one and the same chief apostle. But when it was said to him: 'I will give unto thee the keys of the kingdom of heaven, and whatsoever thou shalt bind on earth shall be bound in heaven, and whatsoever thou shalt loose on earth shall be loosed in heaven,' he represented the universal church which in this world is shaken by divers temptations, even as by torrents of rain, by rivers, and tempests, and yet doth not fall, because it is founded upon the Rock, the word from which Peter got his name. For Rock—Petra—does not come from Peter—Petrus—but Peter from Rock, just as the word Christ is not derived from Christian, but Christian from Christ.
"Hence the Lord said: 'On this Rock I will build my church,' because Peter had said before, 'Thou art the Christ, the Son of the living God.' Upon this Rock which thou hast confessed, he said, 'I will build my church.' For Christ was the Rock. Therefore, the church, which is founded on Christ,
