From the Greek word that means 'dipping', baptism in most Christian churches is a sacrament. It is a rite of purification by water, a ceremony invoking the grace of God to regenerate the person, free him or her from sin, and make that person a part of the church. Thus, baptism is usually required for membership in the church. In Roman Catholic and Anglican theology baptism is also held to confer an indelible character on the person, requiring him or her to worship. Formal baptism is performed by immersion (as among the Baptists) or by pouring or sprinkling water on the person to be baptized. This ceremony is accompanied, in churches that accept the dogma of the Trinity, by a formula asking the blessing of Father, Son, and Holy Spirit. In some churches the child is baptized soon after birth and has sponsors (godfather and godmother) who make declarations of faith in his name. The rite is sometimes called christening, and this term is applied especially to the giving of a baptismal name. Other churches withhold baptism until the person is relatively mature. Some Protestant groups, such as the Religious Society of Friends, reject all outward baptismal rites. Similar customs are known in many non-Christian cultures. The baptism of Jesus himself can be considered part of the founding of the Christian Church.