Water salvation is the pejorative term applied by modern theologians and sectarians to the necessity of baptism to redemption.
Most in Christendom are under the spell of Calvinism, which holds that man has no obligation or opportunity regarding his own salvation, and that if he is redeemed, it will be solely the result of his inactive faith. Passages that extol the power of faith are stripped of any inherent human effort and rendered passive and idle so that salvation can be imposed upon a believer according to the arbitrary whim of the Holy Spirit (see James 2:14-26).
While confession and repentance also require a certain amount of effort, only water baptism is minimized and mischaracterized to the degree that its adherents are reduced to such contempt (Matthew 10:32-39).
Yet no one contends that a person is saved by water baptism alone or that the liquid in the creek, baptistery or pool is invested with supernatural power. The cries against “water salvation” are an assault on a straw man, tilting against a windmill.
Water has always occupied a place in God’s scheme of redemption. Noah had to sail upon it, the pilgrims had to cross through and then over it, Naaman had to dip in it. All complied – whether faced with an impending deluge, pursued by Egyptian armies, standing on the border of Canaan, or hoping for a leprosy cure. All complied because they had faith in the one who promised relief on the other side. Neither fresh rain nor river water possessed any inherent supernatural power, but the faithful compliance of the candidates for grace used the water to obey the divine order.
As prominent as those events are in the Old Testament, water is even more notable in the gospels and the New Testament, where John, Jesus and their evangelistic followers consistently administered baptism to the faithful and penitent. After three years of “preaching a baptism of repentance for the remission of sins,” Jesus made it a part of the Great Commission, which has motivated evangelism for almost two millennia since (Luke 3:3, Matthew 28:18-20). Jesus reasoned, “Whoever believes and is baptized will be saved, but whoever does not believe will be condemned” (Mark 16:16).
The most prolific New Testament writer, the apostle Paul, consistently upheld and practiced water baptism as a righteous requirement – not a work of merit that independently canceled sin, but as a faithful response to the invitation of grace (Romans 6:1-6, Galatians 3:27, Colossians 2:11-13).
The apostle Peter illustrates the necessity of baptism with a reminder of Noah’s ark. “God's patience waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight persons, were brought safely through water. Baptism, which corresponds to this, now saves you, not as a removal of dirt from the body but as an appeal to God for a good conscience, through the resurrection of Jesus Christ” (First Peter 3:20-21).