"Then Jesus came from Galilee to the Jordan to John, to be baptized by him." (Matthew 3:13)
One of the most puzzling things about the life of Jesus is his baptism. John baptized people for repentance who confessed their sins, yet Jesus was absolutely sinless and he came to John to be baptized. You can understand why John would balk at the idea. Why would someone who was sinless submit to a rite that is intended for repentant sinners? Jesus answer--it was to "fulfill all righteousness." However, this seems ambiguous to us. What does it mean to fulfill all righteousness? Here Matthew uses the same word, to fulfill, as the fulfillment formulas which speak of the fulfillment of Old Testament prophecies; however, this text does not follow that formula, and and there does not seem to be any Old Testament prophecy of a baptism for the Messiah. "Fulfilling all righteousness" must mean something else. Absolute certainty is not possible given the ambiguity of the statement, but it seems that there is consensus on a few things. First, Jesus was putting his stamp of approval on the ministry of John. By submitting to John's baptism, he demonstrates that John's ministry is a legitimate predecessor to his own. Second, Jesus is obeying the Father's will. This is evident in God's words from heaven immediately after the baptism. Third, Jesus baptism points forward to his death. The fact that Jesus was submersed under the water and then rose out of the water has the same symbolic significance as Christian baptism. In Christian baptism the immersion of the believer symbolizes Christ's death and burial and as the believer rises out of the water we symbolically see how believers have risen with Christ to live a new life. Jesus baptism presents this same picture. The one who would bring baptism with the Holy Spirit and fire began his ministry by being baptized--pointing to his own death, burial, and resurrection. Finally, in his baptism, Jesus identified with his people. As it was said, John's baptism was a baptism of repentance for those who confessed sin, and Jesus had no sin to confess. In his baptism, Jesus oneness with his people and his substitutionary atonement is foreshadowed. The one who took our punishment and who took our sin upon himself to bear God's wrath, submitted to the same rite of baptism that he commands all of his people to participate in. As believers are baptized, we announce to the world that we are united to Christ in his death, burial and resurrection. When Jesus was baptized, he announced to the world that he is united to repentant sinners. We can be thankful for Jesus baptism because it reminds us of the great exchange. He took our sin and we have received his imputed righteousness. In our union with him we we truly live, and our old selves have died with him.
"For if we have been united with him in a death like his, we shall certainly be united with him in a resurrection like his. We know that our old self was crucified with him in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin." (Romans 6:5-6)