What then says Christ? You are Simon, the son of Jonas; you shall be called Cephas. Thus since you have proclaimed my Father, I too name him that begat you; all but saying, As you are son of Jonas, even so am I of my Father. Else it were superfluous to say, You are 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 you, You are Peter, and upon this rock will I build my Church; Matthew 16:18 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 you are shortly to hear that I shall be betrayed and crucified.
Then He mentions also another honor. And I also will give you the keys of the heavens. But what is this, And I also will give you? As the Father has given you to know me, so will I also give you.
And He said not, I will entreat the Father (although the manifestation of His authority was great, and the largeness of the gift unspeakable), but, I will give you. What dost Thou give? tell me. The keys of the heavens, that whatsoever you shall bind on earth, shall be bound in Heaven, and whatsoever you shall loose on earth, shall be loosed in Heaven. How then is it not His to give to sit on His right hand, and on His left, Matthew 20:23 when He says, I will give you?
Do you see how He, His own self, leads Peter on to high thoughts of Him, and reveals Himself, and implies that He is Son of God by these two promises? For those things which are peculiar to God alone, (both to absolve sins, and to make the church in capable of overthrow in such assailing waves, and to exhibit a man that is a fisher more solid than any rock, while all the world is at war with him), these He promises Himself to give; as the Father, speaking to Jeremiah, said, He would make him as a brazen pillar, and as a wall; Jeremiah 1:18 but him to one nation only, this man in every part of the world.
I would fain inquire then of those who desire to lessen the dignity of the Son, which manner of gifts were greater, those which the Father gave to Peter, or those which the Son gave him? For the Father gave to Peter the revelation of the Son; but the Son gave him to sow that of the Father and that of Himself in every part of the world; and to a mortal man He entrusted the authority over all things in Heaven, giving him the keys; who extended the church to every part of the world, and declared it to be stronger than heaven. For heaven and earth shall pass away, but my word shall not pass away. Matthew 24:35 How then is He less, who has given such gifts, has effected such things?
And these things I say, not dividing the works of Father and Son (for all things are made by Him, and without Him was nothing made which was made): but bridling the shameless tongue of them that dare so to speak.
But see, throughout all, His authority: I say unto you, You are Peter; I will build the Church; I will give you the keys of Heaven.