Baptism is the outward sign of our inward change.
"For Christ also suffered once for sins, the righteous for the unrighteous, to bring you to God. He was put to death in the body but made alive in the Spirit. After being made alive, he went and made proclamation to the imprisoned spirits— to those who were disobedient long ago when God waited patiently in the days of Noah while the ark was being built. In it only a few people, eight in all, were saved through water, and this water symbolizes baptism that now saves you also— not the removal of dirt from the body but the pledge of a clear conscience toward God. It saves you by the resurrection of Jesus Christ, who has gone into heaven and is at God’s right hand— with angels, authorities and powers in submission to him."