Protestant affirmation of biblical teaching
A person is justified by faith because of the work of Christ alone. Forgiveness of sins, or atonement, is received by the application of Christ’s blood. Baptism is a gift given as a sign and seal of the Christian’s inward heart-change, and God’s faithfulness in his covenant promise. God’s people necessarily observe his commandments in obedience and as a demonstration of, never as the meritorious ground of, justifying faith.
(The Westminster Confession of Faith, Chapter XXVIII: Of Baptism) “I. Baptism is a sacrament of the New Testament, ordained by Jesus Christ, not only for the solemn admission of the party baptized into the visible Church; but also to be unto him a sign and seal of the covenant of grace, of his ingrafting into Christ, of regeneration, of remission of sins, and of his giving up unto God, through Jesus Christ, to walk in the newness of life. Which sacrament is, by Christ’s own appointment, to be continued in His Church until the end of the world.
V. Although it is a great sin to contemn or neglect this ordinance, yet grace and salvation are not so inseparably annexed unto it, as that no person can be regenerated, or saved, without it: or, that all that are baptized are undoubtedly regenerated.”
In Orthodox Christian doctrine, there is room for interpretation on the efficacy of baptism as a means of salvation. However, in both Roman Catholicism and Mormonism, “baptismal regeneration” is inescapable, because it is crystallized in their respective doctrinal systems that baptism is necessary for salvation.
In other words, no matter what really makes sense to them, if they hold to their own doctrine, Roman Catholics and Mormons have to believe it.