The New Testament is full of teaching as to the meaning, the nature, and the effect of Christian baptism. In John iii. Jesus describes it as a rebirth by water and the Holy Spirit without which a man cannot enter the Kingdom of God. St Peter calls on his hearers to repent and be baptised for the remission of sins, promising them the gift of the Holy Spirit. And St Paul (Romans vi.) makes use of the symbolism of baptism (which was usually by immersion) to point out that the Christian shares in the death and resurrection of Christ, dying to sin and rising to righteousness.
The Roman Catholic teaching on baptism (repeated by the Church of England in its catechism) is that it washes away and forgives all sin (both original sin and actual sins committed before baptism), that it unites the recipient to Christ and makes him a member of his Body, the Church, and that it bestows upon him, at any rate in germ, a new nature, which has to be nourished and developed until it replaces the old fallen manhood. On this view, since baptism confers a new nature permanently, it can never be repeated.
The outward sign of baptism is washing with water, accompanied by the words 'I baptise thee in the name of the Father and of the Son and of the Holy Spirit' (in Eastern churches, 'the servant of God is baptised'). The person may be totally immersed in the water, or it may be poured over the body (normally over the head). The action is traditionally performed three times, once at each of the three divine names. The water should wash the skin of the recipient, i.e. it must flow over it. For that reason affusion (pouring) is a proper method, while aspersion (sprinkling) is an uncertain and improper method. Affusion is now the normal method in the Western Church, though immersion is permitted and was general earlier, as the ancient baptistries in Italy (e.g. Naples) show.
The normal and regular minister of the sacrament is a priest; but in an emergency anybody may administer baptism, even perhaps one who has not been baptised or who is not a Christian.
The proper subject of baptism is any unbaptised person. In the case of a person above the age of discretion (i.e. capable of discerning right from wrong and so of sin, and normally older than five to seven) the proper dispositions are necessary, i.e. faith and repentance. In the case of infants these dispositions are adequately expressed by adult sponsors who promise to bring them up to have the right dispositions when they are capable of them.
At the Reformation, Calvinists and Zwinglians repudiated most of the sacramental teaching of the Church, concerning baptism, though they retained the rite (as required in Scripture) as a symbol of repentance and of incorporation into Christ. The baptists and anabaptists rejected infant baptism, arguing that there was no evidence for it from Scripture, and that it was a meaningless rite apart from conscious faith and repentance, expressed by the individual recipient.
Baptism in the apostolic Church was mainly of adults, since the greater number of converts were adult Jews, proselytes, or pagans. It seems certain, however, that infants were included in some of the baptisms of whole households mentioned in Acts (e.g. xvi. 32-3). Children had always a recognised place in the Jewish Church, and it is clear that the new dispensation did not abolish that position (Mark x. 13-14). The baptism of infants was a natural corollary from the circumcision of infants which it replaced. Nevertheless, the severe discipline imposed by the early Church on its members who committed grave sins after baptism led many (especially after the conversion of the Empire under Constantine had diluted the faithful with many formal Christians) to postpone baptism until late in life, so as to leave as little scope as possible for such sins and to escape responsibility. This abuse was remedied by the development of a more lenient penitential discipline, and of confession. The rite of baptism was accompanied in the early Church by a number of other striking ceremonies. The Protestant reformers abandoned all of these, but the Church of England retained the signing of the head of the infant with a cross (though consecrated oil was no longer used for the purpose). The custom of bestowing a Christian name at baptism naturally derived from the similar Jewish practice at circumcision (Luke i. 59-63; ii. 21). But it properly means merely that the person is addressed by name in recognition of personality. Another name for baptism in England is christening.