Albert Barnes on John 1:42

Cephas. This is a Syriac word, meaning the same as the Greek word Peter, a stone. Mt 16:17. The stone, or rock, is a symbol of firmness and steadiness of character--a trait in Peter's character after the ascension of Jesus that was very remarkable. Before the death of Jesus he was rash, headlong, variable; and it is one proof of the omniscience of Jesus that he saw that Peter would possess a character that would be expressed appropriately by the word stone or rock. The word Jonas is a Hebrew word, whose original signification is a dove. It may be that Jesus had respect to that when he gave Simon the name Peter. "You now bear a name emblematic of timidity and inconstancy. You shall be called by a name denoting firmness and constancy."

(k) "thou shalt be called Cephas" Mt 16:18 (7) "A Stone" or, "Peter"