Baptism: What is the purpose of water baptism
 in the New Testament?

The purpose of water baptism is clearly revealed in the New Testament.  Even though much confusion exists in the religious world concerning the purpose of water baptism, the word of God is not confusing pertaining to this subject.  I Cor. 14:33 "For God is not the author of confusion", but as Jesus said in John 8:32 "And ye shall know the truth, and the truth shall make you free". The truth about baptism can be known.

In Mark 16:16 Jesus said "He that believeth and is baptized shall be saved". The baptism spoken of here is the "one baptism" mentioned in Eph. 4:5 which is water baptism, the same as to which the Ethiopian was obedient to, Acts 8:38-39.  So we see in Mark 16:16, water baptism is connected to man's salvation. We see this connection also in Acts 2:37-38 when the crowd asked, "Men and brethren, what shall we do?" Peter's reply was "Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins". Water baptism then is for the remission of sins in order to be saved. Remember Isaiah 59:2 says, "But your iniquities have separated between you and your God". One's sins separate one from God.   Separation from God is spiritual death,..... one is lost. Those who have obeyed Peter's command to repent and be baptized and have had their sins remitted are no longer separated from God. They now enjoy a new relationship with God through their obedience to the gospel of Christ.

Also, something else takes place simultaneously along with the forgiveness of sins when one is baptized.  In Eph. 1:3 it says God "hath blessed us with all spiritual blessings in heavenly places in Christ", one of which is, the blessing of salvation.  II Tim. 2:10 says "Therefore I endure all things for the elect's sakes, that they may also obtain the salvation which is in Christ Jesus with eternal glory". Since all spiritual blessings, including salvation are in Christ, then it is of necessity that one be in Christ to be saved. Without any doubt at all,  Rom. 6:3 teaches that we are "baptized into Jesus Christ"Gal. 3:27 teaches the same truth: "For as many of you as have been baptized into Christ have put on Christ". 

The word of God teaches no other way to get "into" Christ except by "being baptized into him". This makes baptism an absolute necessity to be obeyed in order to be saved. This is the purpose of water baptism, clearly defined in the scriptures.