John preaches a message of repentance and baptizes in this message. He points to the coming savior, one who is greater. 

John 1:24-28

(Now they had been sent from the Pharisees.) They asked him, “Then why are you baptizing, if you are neither the Christ, nor Elijah, nor the Prophet?” John answered them, “I baptize with water, but among you stands one you do not know, even he who comes after me, the strap of whose sandal I am not worthy to untie.” These things took place in Bethany across the Jordan, where John was baptizing.