When should a person be re-baptized?

Many people have questions about re-baptism. When should this be done? What if a person grows in their knowledge and understanding from when they were initially baptized? We should keep in mind that we will always be growing, but this doesn't mean that the power of Jesus' blood that saved us initially has weakened or changed (Acts 4:12; 1 John 3:20). Verses Referenced: Matthew 28:19-20; Acts 2:38, 22:16, Colossians 2:11-13; Galatians 3:27; 1 Peter 3:21; Acts 19:1-6; 1 John 3:20, 1 John 5:13; 1 Thessalonians 5:9; John 3:16-17; 2 Peter 3:18; Acts 4:12