For in Christ Jesus you are all sons of God, through faith. For as many of you as were baptized into Christ have put on Christ, Galatians 3:26,27
Could it be any clearer that baptism is necessary to regeneration? Paul links faith and baptism here. It is similar to what our Lord said in the Gospel, "He who believes and is baptized will be saved," (Mk. 16:16). Faith is not merely an intellectual assent to truth. Nor is it a decision made once in the mind, but never, or rarely, acted upon in the life. Faith requires action. Faith apart from works is dead, (Jas. 2:26). That initial action is baptism.
Paul tells us here that when we are baptized, we put on Christ. The picture is of one who removes his former filthy, worn out garment, and dresses himself in a brand new clean one. This is what has happened to us in baptism. The filth and stain of sin was removed. Then we were given the spotless garment of Christ Himself to cover us.
Baptism is not merely a symbol of this action, it is the action. God chooses to work His grace through this sacrament. It is hard for some people to believe this. They think it smacks of magic, or superstition. But that is not true. God can do anything. He has chosen to use blessed water to be the means by which one is born again into His Family, the Church.
So, one may ask, how does this apply to infants who have not yet believed. The children of believing parents are members of the covenant made with God in Christ along with us. Thus we read of entire households that received baptism (Acts 16:15, 33; 18:8). On the day of Pentecost, St. Peter made it clear that baptism and all its benefits, including the gift of the Holy Spirit, was to be given, not only to us, but to our children (Acts 2:38, 39). This works much the same way as it did in the Old Covenant when the children of the Israelites received circumcision, the sign of the covenant made with Abraham in faith, at 8 days old. The children were henceforth considered to be part of the covenant people along with their parents.
Faith and baptism are intended to be linked together in such a way as not to be separated. But they have been separated. What is the result? There are many who have not received the grace of baptism that think of themselves as believers. There are also those who minimalize the importance of baptism and either refuse it, or think nothing of it when they do receive it. Baptism appears as an empty ritual to them, void of meaning.
As we see again the words of St. Paul above, we should be convinced that baptism is much more than empty ritual. It is the means by which we are clothed with Christ. It is that moment when we are initiated into the Faith of Christ.