Acts 8:13-24 is a perfect example of a person being baptized and then subsequently falling away. Simon the sorcerer had turned to the Lord after seeing the miracles performed by Philip and believing the gospel. However, Simon then offered the apostles money that he might receive the power to confer spiritual gifts as he saw them do. Peter rebuked Simon, telling him that his heart was not right with God and that he was poisoned by bitterness and bound by iniquity. What should Simon do? Should he be rebaptized? No. Peter told him to “Repent and pray…” This is essentially the same principle presented by John in I John 1:6-10. John states that even Christians sin. Even a person who is “walking in the light” has sin, else the blood of Jesus would not need to cleanse him. In fact, if a Christian said that he did not have sin, he would be a liar. What is the remedy? John says, “If we confess our sins, He is faithful and just to forgive us our sins…”
Therefore, rebaptism is only necessary when one’s baptism was not for the right reason or with an incorrect understanding. Acts 8:12 gives two prerequisites for baptism: believing the things concerning the kingdom of God and the name of Jesus Christ. To be baptized correctly we must accept the authority of Jesus and believe the things concerning the kingdom.