John 1: 29--33 - lamb of God?

I really don't understand any of what is below. I do "get" the idea that Passover lambs were sacrificed so the the Hebrews were spared in Egypt, so there must be some parallel here.

-------------------------

Jesus the Lamb of God

29The next day John saw Jesus coming toward him and said, “Look, the Lamb of God, who takes away the sin of the world!30This is the one I meant when I said, ‘A man who comes after me has surpassed me because he was before me.’ 31I myself did not know him, but the reason I came baptizing with water was that he might be revealed to Israel.”

32Then John gave this testimony: “I saw the Spirit come down from heaven as a dove and remain on him. 33I would not have known him, except that the one who sent me to baptize with water told me, ‘The man on whom you see the Spirit come down and remain is he who will baptize with the Holy Spirit.’ 34I have seen and I testify that this is the Son of God.”