One nourishes faith by patient obedience to God's commandments. Through the Atonement, if one repents, Christ's mercy satisfies the demands of justice.
Baptism has several purposes.
It is a symbolic washing and cleansing of sins and is prerequisite to membership in the Church. The prescribed method of baptism is by immersion in water by a priest in the Aaronic Priesthood or by one who holds the Melchizedek Priesthood. The gift of the Holy Ghost is conferred by the laying-on of hands by a holder of the Melchizedek Priesthood . Applying the Atonement to Life's Experiences. Salt Lake City, 1989.