He brought him to Jesus. Jesus looked at him, and said, "You are Simon the son of Jonah. You shall be called Cephas" (which is by interpretation, Peter).

 Something had happened at the baptism of Jesus which had convinced John beyond all doubt that Jesus was the Son of God. As the fathers of the church saw centuries ago, it was something which only the eye of the mind and soul could see. But John saw it and was convinced. 