Baptism

This is a new and an everlasting covenant... Wherefore, although a man should be baptized an hundred times it availeth him nothing, for you cannot enter in at the strait gate by the law of Moses, neither by your dead works. Doctrine & Covenants 22:1-2

Early converts to the Church wondered if they needed to be baptized again if they had previously been baptized by immersion in another church. The Lord instructed the Saints that his house is a house of order and that certain principles and practices are eternal and cannot be bypassed. An ordinance performed without the Lord’s true authority is invalid; no covenant is established; no sealing by the Spirit takes place. Dead works are just that—dead, without power or efficacy. Every ordinance depends upon the presence of the Spirit for life. The Holy Ghost must ratify, or seal, an ordinance for it to be a valid, living covenant (D&C 13 2:7). For that to be possible, both proper priesthood authority to transact the ordinance and worthiness on the part of the covenant maker are necessary (Articles of Faith 1:5). Thus, baptism is both a new and an everlasting covenant, revealed anew to the Saints in the dispensation of the fulness of times and binding in all dispensations. (Robert L. Millet and Lloyd D. Newell. Draw Near Unto Me: Daily Reflections on the Doctrine and Covenants. 72)