Christian baptism is the immersion of a believer in water in the name of the Father, the Son, and the Holy Spirit. It is an act of obedience symbolizing the believer's faith in a crucified, buried, and risen Savior and the believer's death to sin, the burial of the old life, and the resurrection to walk in newness of life in Christ Jesus. It is a testimony to his faith in the final resurrection of the dead. Being a church ordinance, it is prerequisite to the privileges of church membership and to the Lord's Supper.
The word for baptize in Greek is baptizo, which means "to dip, plunge, submerge, or immerse." Baptism in the New Testament was related to the ministry of both John the Baptist and of Jesus. John's baptism was symbolic of one's repentance from sin and of willingness to participate in the kingdom of God (Matt. 3:6-8; Luke 3:3-16).
Jesus submitted to John's baptism (Matt. 3:16) not to demote repentance but to authenticate John's ministry, to set an example for His followers, and to dedicate Himself publicly to His redemptive ministry. In so doing Jesus symbolized His death, burial, and resurrection.
Baptism translates baptisma, the meaning in the act of baptism, namely, a symbol of what Jesus did to save us - death, burial, and resurrection - and what He does in the believer - death to the old life, its burial, and resurrection to a new life in Christ.
Keeping in mind the meaning of baptisma, what is the significance of believer's baptism? Is it sacramental in nature and necessary for salvation, or is it symbolic in nature? The word it self strongly suggests the latter. The idea of baptismal regeneration did not appear in Christian teachings until late in the second and early in the third centuries. However, by the late second and early third centuries, baptismal regeneration came to be accepted by the group that later evolved into the Roman Catholic Church.
That immersion is the original form of baptism is generally agreed. Baptizo itself teaches that neither pouring nor sprinkling constitutes New Testament baptism. Because of the later belief in baptismal regeneration, the practice arose of pouring water all over a sick person. This was called clinical baptism. Later, water was poured only on the head.
It should be noted that while the verbs for pour and sprinkle appear in the Testament, neither is used for baptism. No usage has been found where baptizo means either pour or sprinkle. The practice of sprinkling for baptism gradually replaced immersion in the Catholic Church and when it divided into the Roman and Greek branches, the latter retained immersion. It was not until the 13th century that sprinkling became the official mode of Roman Catholic baptism.