In submitting to baptism, Jesus identifies with sinners. As John reminds us, however, the baptism Jesus brings is a baptism with the Holy Spirit and with fire. John prepares the way for Jesus to come in judgment against sinners, but Jesus identifies with those very sinners he came to judge. His is a judgment of separation. The wheat will be separated from the chaff, but the standard of judgment will not be how "religious" you are. Rather, it will be whether or not you have identified with the Christ who identifies with you.
John's preaching of fiery judgment is tempered by Jesus' humble action of identification. God's judgment is real and very much present and imminent. To proclaim it with integrity, however, we must identify with the sinners--the very sinners whom Jesus came to judge, but longs to save.
This is the true tension in which we live as citizens of the kingdom of God in the midst of the kingdom of this world. It is the tension between incarnation and identification. We are to live as the ongoing incarnation of Christ in the world, yet also identify with the sinners. In fact, such identification is part and parcel to incarnational living. We must recognize that there is no one who stands in more need of redemption than ourselves. We do not look to ourselves, however, for that redemption. We look to Christ, and when we look to Christ, we look to the One who calls us to live by his example. He was without sin, yet became sin on our behalf. Thus, the tension between incarnation and identification is the definitive Christian life. We cannot live incarnationally without identifying with sinners, yet we cannot identify with sinners without looking to and placing our whole trust in the One who says, "Follow me."