A.T. Robertson Commentary 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)." — John 1:42 (ASV)

Looked upon him (εμβλεψας αυτω). See verse 36 for same word and form of John's eager gaze at Jesus. Luke uses this word of Jesus when Peter denied him (Luke 22:61).

He brought him (ηγαγεν αυτον). Effective second aorist active indicative of αγο as if Andrew had to overcome some resistance on Simon's part.

Thou shalt be called Cephas (συ κληθηση Κηφας). Apparently before Simon spoke. We do not know whether Jesus had seen Simon before or not, but he at once gives him a nickname that will characterize him some day, though not yet, when he makes the noble confession (Matthew 16:17f.), and Jesus will say, "Thou art Peter." Here the future passive indicative of καλεω is only prophecy. The Aramaic Χηφας (rock) is only applied to Simon in John except by Paul (1 Corinthians 1:12; Galatians 1:18, etc.). But the Greek Πετρος is used by all. In the ancient Greek πετρα was used for the massive ledge of rock like Stone Mountain while πετρος was a detached fragment of the ledge, though itself large. This distinction may exist in Mt 16:17f. , except that Jesus probably used Aramaic which would not have such a distinction.