Read John 1:29-42
29 The next day John saw Jesus coming to him, and said, “There is the Lamb of God, who takes away the sin of the world! 30This is the one I was talking about when I said, ‘A man is coming after me, but he is greater than I am, because he existed before I was born.’ 31I did not know who he would be, but I came baptizing with water in order to make him known to the people of Israel.”
32 And John gave this testimony: “I saw the Spirit come down like a dove from heaven and stay on him. 33I still did not know that he was the one, but God, who sent me to baptize with water, had said to me, ‘You will see the Spirit come down and stay on a man; he is the one who baptizes with the Holy Spirit.’ 34I have seen it,” said John, “and I tell you that he is the Son of God.”
35 The next day John was standing there again with two of his disciples, 36when he saw Jesus walking by. “There is the Lamb of God!” he said.
37 The two disciples heard him say this and went with Jesus. 38Jesus turned, saw them following him, and asked, “What are you looking for?”
They answered, “Where do you live, Rabbi?” (This word means “Teacher”.)
39 “Come and see,” he answered. (It was then about four o’clock in the afternoon.) So they went with him and saw where he lived, and spent the rest of that day with him.
40 One of them was Andrew, Simon Peter’s brother. 41At once he found his brother Simon and told him, “We have found the Messiah.” (This word means “Christ”.) 42Then he took Simon to Jesus.
Jesus looked at him and said, “Your name is Simon son of John, but you will be called Cephas.” (This is the same as Peter and means “a rock”.) 
As John the Baptist recognizes Jesus he says “Here is the lamb of God who takes away the sins of the World.” Later on he reminds the disciples; “…he is the one who baptizes with the Holy Spirit.” Unlike water which just washes the outside of a person; the Holy Spirit is able to purify our hearts.
Lord, baptize me with your Holy Spirit. Take away my sins. Transform my heart.