Baptism is a picture of how the believer's life has been changed through our acceptance of Christ as Lord and Savior. Baptism shows that we are "buried" with Him, and "raised" to walk in the newness of the life He has given us. In other words, "Down with the old...up with the new."
"Therefore we are buried with Him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life." - Romans 6:4
Christian baptism is the immersion of the believer in water, whereby it is an act of obedience that shows a good conscience toward God. Through the act of baptism believers are unified, testifying that we belong together. The inner washing of the sin from our lives must come first through salvation, and then we are to follow through with believer's baptism. If it was important to Jesus, then make no mistake about it, it is important.
"The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ." - 1st Peter 3:21
"Then they that gladly received his word were baptized..." - Acts 2:41