On his first visit on the evening of September 21, 1823, the angel Moroni quoted the prophecy from Malachi 4:5–6 to the Prophet Joseph Smith “with a little variation from the way it reads” (Joseph Smith—History 1:36–39; see also D&C 2). This prophecy was fulfilled on April 3, 1836, in the Kirtland Temple when Elijah appeared and restored the priesthood keys to Joseph Smith and Oliver Cowdery (see D&C 110:13–16). From this first visit to the end of his ministry, the Prophet Joseph Smith continually mentioned Malachi’s prophecy and the mission of Elijah.
In addition to the prophetic explanation he gave in Doctrine and Covenants 128:17–18, the Prophet Joseph Smith also taught: “Elijah was the last Prophet that held the keys of the Priesthood, and who will, before the last dispensation, restore the authority and deliver the keys of the Priesthood, in order that all the ordinances may be attended to in righteousness. It is true that the Savior had authority and power to bestow this blessing; but the sons of Levi were too prejudiced. ‘And I will send Elijah the Prophet before the great and terrible day of the Lord,’ etc., etc. Why send Elijah? Because he holds the keys of the authority to administer in all the ordinances of the Priesthood; and without the authority is given, the ordinances could not be administered in righteousness” (History of the Church, 4:211).
The Prophet Joseph Smith also explained the meaning of the word turn and its application in our lives:
“The word turn here [in Malachi 4:5–6] should be translated bind, or seal. But what is the object of this important mission? or how is it to be fulfilled? The keys are to be delivered, the spirit of Elijah is to come, the Gospel to be established, the Saints of God gathered, Zion built up, and the Saints to come up as saviors on Mount Zion.
“But how are they to become saviors on Mount Zion? By building their temples, erecting their baptismal fonts, and going forth and receiving all the ordinances, baptisms, confirmations, washings, anointings, ordinations and sealing powers upon their heads, in behalf of all their progenitors who are dead, and redeem them that they may come forth in the first resurrection and be exalted to thrones of glory with them; and herein is the chain that binds the hearts of the fathers to the children, and the children to the fathers, which fulfills the mission of Elijah” (History of the Church, 6:184).