Christian perfection is the name given to the process or the event of achieving spiritual maturity or perfection; it is a theological concept that exists within many denominations of Christianity. The ultimate goal of this process is union with God characterized by pure love of God and other people as well as personal holiness or sanctification. Other terms used for this or similar concepts include entire sanctification, perfect love, the baptism with the Holy Spirit, the indwelling of the Holy Spirit, baptism by fire, the second blessing, and the second work of grace.

Baptism is a Christian sacrament of initiation almost invariably with the use of water. It may be performed by sprinkling or pouring water on the head, or by immersing in water either partially or completely, traditionally three times, once for each person of the Trinity. The synoptic gospels recount that John the Baptist baptised Jesus. Baptism is considered a sacrament in most churches, and as an ordinance in others. Baptism according to the Trinitarian formula, which is done in most mainstream Christian denominations, is seen as being a basis for Christian ecumenism, the concept of unity amongst Christians. Baptism is also called christening, although some reserve the word "christening" for the baptism of infants. In certain Christian denominations, such as the Catholic Churches, Eastern Orthodox Churches, Oriental Orthodox Churches, Assyrian Church of the East, and Lutheran Churches, baptism is the door to church membership, with candidates taking baptismal vows. It has also given its name to the Baptist churches and denominations.