The Rock and the Keys
Matthew 16:16-19, Peter's confession, as the early church read it
Few verses have carried more weight than "thou art Peter, and upon this rock I will build my church." It is the great proof-text of the papacy, and the great point of division. So it is worth hearing the early church in its own words, and the striking thing is the range: the Fathers read "the rock" as Peter, or as Peter's confession, or as Christ Himself whom Peter confessed, and Augustine moved openly toward the last. On the keys, some saw a special place for Peter, while others insisted the same authority was given to all the apostles, tied to holiness, with Jerome warning clergy against turning it into Pharisee-like power. The Fathers below, with a plain restatement and an honest map of where the traditions later parted.
Each Father's words are verbatim and attributed (Catena Aurea, public domain, lightly corrected for scan errors). The box marked "In plain terms" is our own restatement, never the Father's words.
Matthew 16:16-18 · KJVAnd Simon Peter answered and said, Thou art the Christ, the Son of the living God… And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
"On this faith and confession I will build my Church. Herein shewing that many should believe what Peter had confessed, and raising his understanding, and making him His shepherd."
St. John Chrysostom"I have said in a certain place… 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… as meaning upon Him whom Peter had confessed… For it is not said to him, Thou art the rock, but, Thou art Peter. But the rock was Christ, whom because Simon thus confessed… he was named Peter. Let the reader choose whether of these two opinions seems to him the more probable."
St. AugustineThe Fathers did not read this with one voice. Chrysostom takes the rock to be "this faith and confession" Peter had just made. Augustine, who had once said the Church was built on Peter, says plainly that he later came to read the Rock as Christ Himself, whom Peter confessed, and leaves the reader to weigh the two. The fixed point for them is not Peter's person in isolation but the confession "Thou art the Christ," the faith on which the Church stands.
Matthew 16:19 · KJVAnd 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.
"This power of binding and loosing, though it seems given by the Lord to Peter alone, is indeed given also to the other Apostles, and is even now in the Bishops and Presbyters in every Church. But Peter received in a special manner the keys… and a supremacy of judicial power."
Rabanus Maurus"This power was committed specially to Peter, that we might thereby be invited to unity. For He therefore appointed him the head of the Apostles, that the Church might have one principal Vicar of Christ… But if there were many heads in the Church, the bond of unity would be broken."
Glossa Ordinaria"Bishops and Presbyters, not understanding this passage, assume to themselves something of the lofty pretensions of the Pharisees, and suppose that they may either condemn the innocent, or absolve the guilty; whereas what will be enquired into before the Lord will be… the life of him that is being judged… the Bishop or Presbyter binds or looses… when he has heard the varieties of their sins, he knows who is to be bound, and who loosed."
St. Jerome"Let him then be without blame who binds or looses another, that he may be found worthy to bind or loose in heaven… to him who shall be able by his virtues to shut the gates of hell, are given in reward the keys of the kingdom of heaven."
OrigenOn the keys the range is just as real. Some Fathers (and the later Western voices especially) saw a special place for Peter, a head, a principle of unity. But the same Fathers say the binding-and-loosing was "given also to the other Apostles" and "is even now in the Bishops and Presbyters in every Church" (Jesus says the same words to all the disciples in Matthew 18:18). And two cautions ring out: Jerome warns clergy not to take "the lofty pretensions of the Pharisees," the priest does not make a man guilty or clean any more than the priest in Leviticus made a man a leper; he discerns and declares. And Origen ties the keys to holiness: only the blameless can truly bind or loose. The authority is real, shared, declarative, and bound to a holy life, not a personal monarchy.
Where the traditions diverge
This is the classic dividing passage, so the honest map matters. The Catholic tradition reads Peter as the rock and the keys as the office of the papacy, handed down to the bishops of Rome with universal jurisdiction. The Orthodox read the rock as Peter's confession (or Christ confessed) and the keys as given to all the apostles and their successor-bishops collegially, honoring Rome's ancient primacy of honor but rejecting universal papal supremacy. Protestants read the rock as the confession or Christ Himself, and the keys as the gospel and the ministry of the whole church, not a papal office.
The early church, as the Fathers above show, held a genuine range, and the broad and early threads, the rock as the confession or Christ, the keys given to all the apostles and tied to faith and holiness, sit alongside a developing language of Petrine primacy that the Western church later built into the full doctrine of papal supremacy. The reason it belongs in a study of drift is not to deny Peter's honor, which Scripture and the Fathers both grant, but to show that the developed papal monarchy is a later growth from earlier and more modest soil, and that the church's foundation, in the Fathers' own most considered words, is the confession that Jesus is the Christ, the Son of the living God.
Patristic text from the Catena Aurea (public domain, transcription lightly corrected). Scripture in the King James Version; the plain-language lines are our own restatement, not the Fathers' words. See also the eschatology and church letters, this passage in the Study Bible, and Matthew 16 at BibleHub.