As regards the oft-quoted Mt. 16:18
Augustine, sermon:
"Christ, you see, built his Church not on a man but on Peter's confession. What is Peter's confession? 'You are the Christ, the Son of the living God.' There's the rock for you, there's the foundation, there's where the Church has been built, which the gates of the underworld cannot conquer. John Rotelle, O.S.A., Ed., The Works of Saint Augustine , © 1993 New City Press, Sermons, Vol III/6, Sermon 229P.1, p. 327
Upon this rock, said the Lord, I will build my Church. Upon this confession, upon this that you said, 'You are the Christ, the Son of the living God,' I will build my Church, and the gates of hell shall not conquer her (Mt. 16:18). John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City, 1993) Sermons, Volume III/7, Sermon 236A.3, p. 48.
Augustine, sermon:
For petra (rock) is not derived from Peter, but Peter from petra; just as Christ is not called so from the Christian, but the Christian from Christ. For on this very account the Lord said, 'On this rock will I build my Church,' because Peter had said, 'Thou art the Christ, the Son of the living God.' On this rock, therefore, He said, which thou hast confessed, I will build my Church. For the Rock (Petra) was Christ; and on this foundation was Peter himself built. For other foundation can no man lay than that is laid, which is Christ Jesus. The Church, therefore, which is founded in Christ received from Him the keys of the kingdom of heaven in the person of Peter, that is to say, the power of binding and loosing sins. For what the Church is essentially in Christ, such representatively is Peter in the rock (petra); and in this representation Christ is to be understood as the Rock, Peter as the Church. Augustine Tractate CXXIV; Philip Schaff, Nicene and Post-Nicene Fathers: First Series, Volume VII Tractate CXXIV (http://www.ccel.org/ccel/schaff/npnf107.iii.cxxv.html)
Augustine, sermon:
And Peter, one speaking for the rest of them, one for all, said, You are the Christ, the Son of the living God (Mt 16:15-16)...And I tell you: you are Peter; because I am the rock, you are Rocky, Peter-I mean, rock doesn't come from Rocky, but Rocky from rock, just as Christ doesn't come from Christian, but Christian from Christ; and upon this rock I will build my Church (Mt 16:17-18); not upon Peter, or Rocky, which is what you are, but upon the rock which you have confessed. I will build my Church though; I will build you, because in this answer of yours you represent the Church. John Rotelle, O.S.A. Ed., The Works of Saint Augustine (New Rochelle: New City Press, 1993), Sermons, Volume III/7, Sermon 270.2, p. 289
Augustine, sermon:
Peter had already said to him, 'You are the Christ, the Son of the living God.' He had already heard, 'Blessed are you, Simon Bar-Jona, because flesh and blood did not reveal it to you, but my Father who is in heaven. And I tell you, that you are Peter, and upon this rock I will build my Church, and the gates of the underworld shall not conquer her' (Mt 16:16-18)...Christ himself was the rock, while Peter, Rocky, was only named from the rock. That's why the rock rose again, to make Peter solid and strong; because Peter would have perished, if the rock hadn't lived. John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City, 1993) Sermons, Volume III/7, Sermon 244.1, p. 95
Augustine, sermon:
...because on this rock, he said, I will build my Church, and the gates of the underworld shall not overcome it (Mt. 16:18). Now the rock was Christ (1 Cor. 10:4). Was it Paul that was crucified for you? Hold on to these texts, love these texts, repeat them in a fraternal and peaceful manner. John Rotelle, Ed., The Works of Saint Augustine (New Rochelle: New City Press, 1995), Sermons, Volume III/10, Sermon 358.5, p. 193
Augustine, Psalm LXI:
Let us call to mind the Gospel: 'Upon this Rock I will build My Church.' Therefore She crieth from the ends of the earth, whom He hath willed to build upon a Rock. But in order that the Church might be builded upon the Rock, who was made the Rock? Hear Paul saying: 'But the Rock was Christ.' On Him therefore builded we have been. Philip Schaff, Nicene and Post-Nicene Fathers (Grand Rapids: Eerdmans, 1956), Volume VIII, Saint Augustin, Exposition on the Book of Psalms, Psalm LXI.3, p. 249. (http://www.ccel.org/ccel/schaff/npnf108.ii.LXI.html)
Augustine, in Retractions,
In a passage in this book, I said about the Apostle Peter: 'On him as on a rock the Church was built.'...But I know that very frequently at a later time, I so explained what the Lord said: 'Thou art Peter, and upon this rock I will build my Church,' that it be understood as built upon Him whom Peter confessed saying: 'Thou art the Christ, the Son of the living God,' and so Peter, called after this rock, represented the person of the Church which is built upon this rock, and has received 'the keys of the kingdom of heaven.' For, 'Thou art Peter' and not 'Thou art the rock' was said to him. But 'the rock was Christ,' in confessing whom, as also the whole Church confesses, Simon was called Peter. But let the reader decide which of these two opinions is the more probable. The Fathers of the Church (Washington D.C., Catholic University, 1968), Saint Augustine, The Retractations Chapter 20.1:.
Thank you. I enjoy your posts and learn a lot.