First, you need to understand that God works covenantally. A covenant is a pact or agreement between two or more parties. The New Testament and Old Testament are New and Old Covenants. The word “testament” comes from the Latin testamentum which means covenant. So, the Bible is a covenant document. If you do not understand covenant you cannot understand, in totality, the issue of baptism because baptism is a covenant sign.
If you fail to understand that God works covenantally and that He uses signs as manifestations of his covenants (rainbow, circumcision, communion, etc.) then you will not be able to understand where baptism fits in God’s covenant system.
Genesis 17: 11 “And ayou shall be circumcised in the flesh of your foreskin, and it shall be the sign of the covenant between Me and you.
Romans 2: 28 For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh. 29 But he is a Jew who is one inwardly; and circumcision is that which is of the heart, by the Spirit, not by the letter; and his praise is not from men, but from God.
If you understand that baptism is a covenant sign, then you can see that it is a representation of the reality of Christ circumcising our hearts (Rom. 2:29; Col. 2:11-12). It is our outward proclamation of the inward spiritual blessing of regeneration. It comes after faith which is a gift of God (Rom. 12:3) and the work of God (John 6:28).
Ephesians 2: 8 For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; 9 not as a result of works, so that no one may boast. (not by something man did such as baptism.)
Galations 2: 21 “I do not nullify the grace of God, for aif righteousness comes through the Law, then Christ died needlessly.” (physical baptism would be considered a law that man must keep)
Saying that baptism is necessary for salvation is dangerous because it is saying that there is something we must do to complete salvation. That is wrong! See Gal. 2:21; 5:4.
The figure of baptism represents the reality of Christ’s death, burial, and resurrection. It is a covenant sign for us. Remember, a covenant sign represents the covenant, it is not the covenant itself. The covenant sign of baptism represents the covenant of grace which is that covenant between God and the Christian where we receive the grace of God through the person of Christ by means of his sacrifice.
Titus 3:5, “he saved us, not because of righteous things we had done, but because of his mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit.”
The washing of rebirth can only be that washing of the blood of Christ that cleanses us. It is not the symbol that saves, but the reality. The reality is the blood of Christ.