Baptism

Baptism refers to the sacrament of initiation in the Catholic and Eastern Orthodox traditions, considered to be necessary for salvation in accordance with Jesus' teaching in John 3:5 Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.. Because of this, infants are baptized a few weeks after being born. In the Catholic ritual, water is poured over the head of the child while the priest repeats the baptismal formula of Matthew 28:19, "I baptize you (name) in the Name of the Father, and of the Son, and of the Holy Spirit. Amen." Adult converts to Catholicism are immersed in water for baptism during Easter vigil.

In the Protestant tradition, the water in John 3:5 is assumed to be the waters of birth and being born again refers to spiritual renewal. Thus baptism becomes an ordinance performed after conversion, and is rarely administered to infants (paedobaptism).