The word baptism is derived from the Greek word "baptizo" which means to immerse or submerge.

Christian baptism symbolizes the death, burial, and resurrection of Christ Jesus.  In Christian baptism, the one being baptized is testifying that they were in Christ Jesus on the cross of Calvary when sin was judged, that they died with Him, were buried with Him, and just as He arose from the dead, they too have arisen to a new life in Him.¹

In the New Testament, Christian baptism is for believers and it represents their new life in Christ Jesus.²  For one to be baptized in water, apart from personal commitment to Christ Jesus, is to no avail.  If water baptism were a requirement for salvation, none who died prior to Christ Jesus' death, burial, and resurrection would have been saved.  Likewise, the thief whom Christ Jesus told would be with Him in Paradise would not have been saved; but he was.³

Christian baptism is not required for salvation, but, rather, is a testimony of what has taken place in the life of the one being baptized; it's an act of obedience, and it's the first step towards discipleship.⁴

Bible References:

¹ (Romans 6:3-4; 2 Corinthians 5:17, 21)

² (2 Corinthians 5:17)

³ (Luke 23:42-43)

⁴ (Matthew 28:19)