He will forgive us of the evil we that we realize and confess. He will also cleanse us of all the evil we commit but do not realize. If we claim that we have committed no evil, we make God a liar and God's word is not in us. In those statements, John reveals some incredible promises from God. First, John wants us to understand that Jesus' cleansing blood does not stop flowing through our lives after we are baptized.
Baptism begins the flow of that cleansing blood.
That atoning blood continues to flow in our lives and to cleanse us from the evil that occurs in us. Second, for the atoning blood to continue to flow in our lives, the Christian must accept these responsibilities. I must honestly accept the fact that evil will always occur in my life. I must honestly commit myself to living in God's light by studying, learning, and understanding His word. I must honestly accept the responsibility to confess to God the evil I commit when I realize that this evil has occurred.