The Gospel of John, Day 9: ch. 1, vv. 32-34

32 Then John gave this testimony: “I saw the Spirit come down from heaven as a dove and remain on him. 33 And I myself did not know him, but the one who sent me to baptize with water told me, ‘The man on whom you see the Spirit come down and remain is the one who will baptize with the Holy Spirit.’ 34 I have seen and I testify that this is God’s Chosen One.”

At the baptism of Jesus, the dove descends on him as a sign of the spirit of God coming down to rest upon him. This also accomplishes God's purpose for John's ministry of baptism: so that Jesus might be revealed to Israel (31). Since Jesus has the spirit of God remaining in him, he baptizes us not with water, but with the holy spirit. Water baptism is a physical sign that Christians are told to practice for many different reasons. However, I do not believe it is a requirement of salvation. Yet baptism of the holy spirit is something that all believers are given when they follow Jesus. What exactly the holy spirit gives us is expounded upon later in John 14-16.

Check out Mark 1:7 also for more about John's baptism and Jesus' baptism.  This is a tricky subject, but I think it is important.