John 1:42

He brought him unto Jesus. Jesus looked upon him and said, Thou art Simon the son of John: thou shalt be called Cephas (which is by interpretation, Peter).

Thou art Simon the son of John ... These are the exact words Jesus used in his confession of Peter (Matthew 16:13f), and the Lord's use of them here appears to have been prompted by his divine foreknowledge of the great confession that Peter would make.

Thou shalt be called Cephas ... This new name assigned to Andrew's brother means "stone" or "pebble"; and for the connection this has with the foundation of the church and such things as the so-called primacy of this apostle, reference is made to extensive discussions of these and related subjects in my Commentary on Matthew, pp. 246-253.

"Cephas" is a Syriac word, and is equivalent to the Greek word [@Petros], which we render "Peter." Both mean a stone, a portion of a rock. [@Petra] means a rock, [@Petros] a piece of rock. Peter was the latter, not the former.[44]

The Lord's perfect understanding of Peter's character the moment he saw him was commented upon by Ryle, thus:

Our Lord here displayed his perfect knowledge of all persons, names, and things. He needed not that any should tell him who and what a person was. Such knowledge was supposed by the Jews to be a peculiar attribute of the Messiah. He was to be one of "quick understanding" (Isaiah 11:3) .... It is a peculiar attribute of God, who alone knows the hearts of men. Our Lord's perfect knowledge of all hearts was one among many proofs of his divinity. His same knowledge appears again in his address to Nathaniel (John 1:47), and in his conversation with the Samaritan woman (John 4:18).[45]

[44] J. C. Ryle, Expository Thoughts on the Gospels (Grand Rapids, Michigan: Zondervan), John I, p. 76.

[45] J. C. Ryle, op. cit., p. 76.