John Calvin on John 1:42

42. Thou art Simon. Christ gives a name to Simon, not as men commonly do, from some past event, or from what is now perceived in them, but because he was to make him Peter, (a stone.) First, he says, Thou art Simon, the son of Jonah. He repeats the name of his father in an abridged form; which is common enough when names are translated into other languages; for it will plainly appear from the last chapter that he was the son of Johanna or John. But all this amounts to nothing more than that he will be a very different person from what he now is. For it is not For the sake of honor that he mentions his father; but as he was descended from a family which was obscure, and which was held in no estimation among men, Christ declares that this will not prevent him from making Simon a man of unshaken courage. The Evangelist, therefore, mentions this as a prediction, that Simon received a new name. I look upon it as a prediction, not only because Christ foresaw the future steadfastness of faith in Peter, but because he foretold what he would give to him. He now magnifies the grace which he determined afterwards to bestow upon him; and therefore he does not say that this is now his name, but delays it till a future time.

Thou shalt be called Cephas. All the godly, indeed, may justly be called Peters (stones,) which, having been Sounded on Christ, are fitted for building the temple of God; but he alone is so called on account of his singular excellence. Yet the Papists act a ridiculous part, when they substitute him in the place of Christ; so as to be the foundation of the Church, as if he too were not founded on Christ along with the rest of the disciples; and they are doubly ridiculous when out of a stone they make him a head. For among the rhapsodies of Gratian there is a foolish canon under the name of Anacletus, who, exchanging a Hebrew word for a Greek one, and not distinguishing the Greek word κεφαλὴ (kephale) from the Hebrew word Cephas, thinks that by this name Peter was appointed to be Head of the Church. Cephas is rather a Chaldaic than a Hebrew word; but that was the customary pronunciation of it after the Babylonish captivity. There is, then, no ambiguity in the words of Christ; for he promises what Peter had not at all expected, and thus magnifies his own grace to all ages, that his former condition may not lead us to think less highly of him, since this remarkable appellation informs us that he was made a new man.

John 1:43-46

43. The next day Jesus wished to go into Galilee, and found Philip, and said to him, Follow me. 44. Now Philip was of Bethsaida, the city of Andrew and Peter. 45. Philip findeth Nathanael, and saith to him, We have found Jesus of Nazareth, the son of Joseph, of whom Moses in the Law, and the Prophets write. 46. Nathanael said to him, Can any good thing come out of Nazareth? Philip said to him, Come and see.