He proves from the renowned confession of the blessed Peter that Christ is God.
But if you prefer the authority of a greater person (although you ought not to slight the authority of any one of either sex, on whom the confession of the mystery confers weight—for whatever may be a persons condition, or however humble his position, yet the value of his faith is not thereby diminished) let us interrogate no beginner or untaught schoolboy, nor a woman whose faith might perhaps appear to be but rudimentary; but that greatest of disciples among disciples, and of teachers among teachers, who presided and ruled over the Roman Church, and held the chief place 2441 in the priesthood as he did in the faith. Tell us then, tell us, we pray, O Peter, thou chief of Apostles, tell us how the Churches ought to believe in God. For it is right that you should teach us, as you were taught by the Lord, and that you should open to us the gate, of which you received the key. Shut out all those who try to overthrow the heavenly house: and those who are endeavouring to enter by secret holes and unlawful approaches: as it is clear that none can enter the gate of the kingdom save one to whom the key bestowed on the Churches is revealed by you. Tell us then how we ought to believe in Jesus Christ and to confess our common Lord. You will surely reply without hesitation: “Why do you consult me as to the way in which the Lord should be confessed, when you have before you my own confession of Him? Read the gospel, and you will not want me myself, when you have got my confession. Nay, you have got me myself when you have my confession; for though I have no weight apart from my confession, yet the actual confession adds weight to my person.” Tell us then, O Evangelist, tell us the confession: tell us the faith of the chief Apostle: did he confess that Jesus was only a man, or God? did he say that there was nothing but flesh in Him, or did he proclaim Him the Son of God? When then the Lord Jesus Christ asked whom the disciples believed and confessed Him to be, Peter, the first of the Apostles, replied—one in the name of all—for the answer of one was to the same effect as the faith of them all. But it was fitting that he should first give the answer, that the order of the answer might correspond to the degree of honour: and that he might outstrip them in confession, as he outstripped them in age. What then does he p. 570 say? “Thou art,” he says, “the Christ the Son of the living God.” 2442 I am obliged, you heretic, to make use of a plain and simple question to confute you. Tell me, I pray, who was He, to whom Peter gave that answer? You cannot deny that it was the Christ. I ask then, what do you call Christ? man or God? Man certainly without any doubt: for hence springs the whole of your heresy, because you deny that Christ is the Son of God. And so too you say that Mary is Christotocos, but not Theotocos, because she was the mother of Christ, not of God. Therefore you maintain, that Christ is only a man, and not God, and so that He is the Son of man not of God. What then does Peter reply to this? “Thou art,” he says, “the Christ, the Son of the living God.” That Christ whom you declare to be only the Son of man, he testifies to be the Son of God. Whom would you like us to believe? you or Peter? I imagine that you are not so shameless as to venture to prefer your own opinion to that of the first of the Apostles. And yet what is there that you would not venture on? or how can you help scorning the Apostle, if you can deny God? “Thou art then,” he says, “the Christ, the Son of the living God.” Is there anything puzzling or obscure in this? It is nothing but a plain and open confession: he proclaims Christ to be the Son of God. Perhaps you will deny that the words were spoken: but the Evangelist testifies that they were. Or do you say that the Apostle told a lie? But it is an awful lie to accuse an Apostle of lying. Or perhaps you will maintain that the words were spoken of some other Christ? But this is a novel kind of monstrous fabrication. What then is left for you? One thing indeed; viz., that since what is written is read, and what is read is true, you should finally be driven by force and compulsion (as you cannot assert its falsehood) to desist from impugning its truth.
S. Matt. xvi. 16.