(Though I actually agree with you that the rock is faith in Christ, not Peter/Catholic Church per se.)
:tsktsk:
**Tertullian **
“[T]he Lord said to Peter, ‘On this rock I will build my Church, I have given you the keys of the kingdom of heaven [and] whatever you shall have bound or loosed on earth will be bound or loosed in heaven’ [Matt. 16:18–19]. . . . Upon you, he says, I will build my Church; and I will give to you the keys, not to the Church; and whatever you shall have bound or you shall have loosed, not what they shall have bound or they shall have loosed” (Modesty 21:9–10 [A.D. 220]).
“Was anything hidden from Peter, who was called the Rock whereon the Church was to be built; who obtained the keys of the kingdom of heaven, and the power of loosing and of binding in heaven and on earth?” (De Praescript Haeret, n.22, p. 209, in Colin Lindsay, The Evidence for the Papacy, (London: Longmans, 1870), 19, c.A.D. 200-220,)
Cyprian of Carthage (251 A.D.)
“The Lord says to Peter: ‘I say to you,’ He says, ‘that you are Peter, and upon this rock I will build my Church, and the gates of hell will not overcome it. And to you I will give the keys of the kingdom of heaven: and whatever things you bind on earth shall be bound also in heaven, and whatever you loose on earth, they shall be loosed also in heaven.’ And again He says to him after His resurrection: ‘Feed my sheep.’ On him He builds the Church, and to him He gives the command to feed the sheep; and although He assigns a like power to all the Apostles, yet He founded a single chair, and He established by His own authority a source and an intrinsic reason for that unity. Indeed, the others were that also which Peter was; but a primacy is given to Peter, whereby it is made clear that there is but one Church and one chair. So too, all are shepherds, and the flock is shown to be one, fed by all the Apostles in single-minded accord. If someone does not hold fast to this unity of Peter, can he imagine that he still holds the faith? If he desert the chair of Peter upon whom the Church was built, can he still be confident that he is in the Church?” (The Unity of the Catholic Church 4 [A.D. 251]).
**Ambrose **
“[Christ] made answer: ‘You are Peter, and upon this rock will I build my Church . . .’ Could he not, then, strengthen the faith of the man to whom, acting on his own authority, he gave the kingdom, whom he called the rock, thereby declaring him to be the foundation of the Church [Matt. 16:18]?” (The Faith 4:5 [A.D. 379]).
"…Christ ‘bestow[ed] the favor of this title upon His disciple, so that HE TOO might be Peter [rock]” (that is, the Rock of the Church in a vicarious sense).
“Peter is called the Rock because, like an immovable rock, he sustains and joins the mass of the entire Christian edifice.” (Ambrose, Sermon 4).
“It is to Peter that he says: ‘You are Peter, and upon this rock I will build my Church’ [Matt. 16:18]. Where Peter is, there is the Church. And where the Church, no death is there, but life eternal” (Commentary on Twelve Psalms of David 40:30 [A.D. 389]).
Augustine
“Let us not listen to those who deny that the Church of God is able to forgive all sins. They are wretched indeed, because they do not recognize in Peter the rock and they refuse to believe that the keys of heaven, lost from their own hands, have been given to the Church” (Christian Combat, 31:33(A.D. 397), in JUR,3:51).
“When, therefore, He had said to His disciples, ‘Will ye also go away?” Peter, that Rock, answered with the voice of all, “Lord, to whom shall we go? Thou hast the words of eternal life’ “ (Homilies on John, Tract 11:5(A.D. 417), in NPNF1,VII:76).
“And the Lord, to him to whom a little before He had said, ‘Blessed thou art, and upon this Rock I will build my Church,’ saith, ‘Go back behind, Satan, an offence thou art to Me.’ Why therefore ‘Satan’ is he, that a little before was ‘blessed,’ and a ‘Rock’ ?” (In Psalms, 56[55]:14[PL 36, 656] (A.D. 418),in NPNF1,VIII:223).
“Peter, who had confessed Him as the Son of God, and in that confession had been called the rock upon which the Church should be built.” (In Psalms, 69:4[PL 36, 869] (A.D. 418), in Butler, 251).
“And if a Jew asks us why we do that, we sound from the rock, we say, This Peter did, this Paul did: from the midst of the rocks we give our voice. But that rock, Peter himself, that great mountain, when he prayed and saw that vision, was watered from above” In Psalms, 104[103]:16(A.D. 418),in NPNF1,VIII:513).
**Pope Leo I **
“[T]he blessed Peter persevering in the strength of the rock, which he has received, has not abandoned the helm of the Church, which he understood. For he was ordained before the rest in such a way that, from his being called the rock, from his being pronounced the foundation, from his being constituted the doorkeeper of the kingdom of heaven, from his being set as the umpire to bind and loose, whose judgments shall retain their validity in heaven, from all these mystical titles we might know the nature of his association with Christ” (Sermons 3:2–3 [A.D. 450]).