Reveal the Priesthood through Elijah

"Behold, I will reveal unto you the Priesthood, by the hand of Elijah the prophet, before the coming of the great and dreadful day of the Lord. And he shall plant in the hearts of the children the promises made to the fathers, and the hearts of the children shall turn to their fathers. If it were not so, the whole earth would be utterly wasted at his coming." D & C 2:2

Planting in the hearts of the children ...

“The turning of the hearts of the children to the fathers is placing or planting in the hearts of the children that feeling and desire which will inspire them to search out the records of the dead. Moreover the planting of the desire and inspiration in their hearts is necessary. This they must have in order that they might go into the house of the Lord and perform the necessary labor for their fathers, who died without a knowledge of the gospel, or without the privilege of receiving the fullness of the gospel.” Doctrines of Salvation 2:127-128