Wikipedia
Baptismal regeneration is the name given to doctrines held by major Christian denominations which maintain that salvation is intimately linked to the act of baptism, without necessarily holding that salvation is impossible apart from it. Etymologically, the term means "being born again" (regeneration, or rebirth) "through baptism" (baptismal). Etymology concerns the origins and root meanings of words, but these "continually change their meaning, … sometimes moving out of any recognisable contact with their origin … It is nowadays generally agreed that current usage determines meaning.” While for Reformed theologian Louis Berkhof, “regeneration” and "new birth" are synonymous, Herbert Lockyer treats the two terms as different in meaning in one publication, but in another states that baptism signifies regeneration.
The term is associated with , where Jesus tells Nicodemus, a Pharisee and member of the Jewish ruling council, that "unless one is born again he cannot see the kingdom of God ... unless one is born of water and the Spirit, he cannot enter the kingdom of God".
One of the earliest of the Church Fathers to enunciate clearly and unambiguously the doctrine of baptismal regeneration ("the idea that salvation happens at and by water baptism duly administered") was Cyprian (c. 200 – 258): "While he attributed all the saving energy to the grace of God, he considered the 'laver of saving water' the instrument of God that makes a person 'born again', receiving a new life and putting off what he had previously been. The 'water of new birth' animated him to new life by the Spirit of holiness working through it."
Adherents of this doctrine include the Roman Catholic, Orthodox, Lutheran, Anglican (especially its High-Church and Anglo-Catholic parties), and Reformed churches. In addition, churches originating out of the American Restoration Movement, mainly the Churches of Christ, are also commonly believed to hold to this doctrine, though they dispute this to be the case.