When Christ appeared to the Nephites, he admonished the priesthood to bless the bread and wine and serve it to those who repent and are baptized in His name (3 Nephi 8:40). Moroni, before sealing up the plates to come forth in the latter days, described in detail how the priesthood are to administer the bread and wine and present them to the people (Moroni 4). Joseph Smith, Jr. later confirmed Moroni’s words, recorded in Doctrine & Covenants Section 17, giving instruction to the priesthood offices authorized to offer the prayers over the bread and wine, and to serve them to the those members of the church baptized by those with priesthood authority.
The prayers over the sacrament and the serving of the emblems (bread and wine) are to be administered ONLY by either a Priest, Elder or High Priest of the church. Below are the exact prayers they were instructed to offer when offering the sacrament of the Lord’s Supper.
PRAYER OVER THE BREAD
O God, the eternal Father, we ask thee in the name of thy Son Jesus Christ, to bless and sanctify this bread to the souls of all those who partake of it, that they may eat in remembrance of the body of thy Son, and witness unto thee, O God the eternal Father, that they are willing to take upon them the name of thy Son, and always remember him, and keep his commandments which he has given them, that they may always have his Spirit to be with them. Amen.
(RLDS D&C 17:22d; Moroni 4:4)
PRAYER OVER THE WINE
O God, the eternal Father, we ask thee in the name of thy Son Jesus Christ, to bless and sanctify this wine to the souls of all those who drink of it, that they may do it in remembrance of the blood of thy Son which was shed for them, that they may witness unto thee, O God, the eternal Father, that they do always remember him, that they may have his Spirit to be with them. Amen.
(RLDS D&C 17:23b and Moroni 5:3)