“Why was it necessary for Elijah to be taken into heaven as he was?” Ensign, Oct. 1973, 76–77
“When Moses and Elijah came to the Savior and to Peter, James, and John upon the Mount, what was their coming for? Was it just some spiritual manifestation to strengthen these three apostles? Or did they come merely to give comfort unto the Son of God in his ministry and to prepare him for his crucifixion? No! That was not the purpose. …
The Prophet Joseph Smith has explained it as follows:
“‘The priesthood is everlasting. The Savior, Moses, and Elias [Elijah, in other words] gave the keys to Peter, James, and John on the Mount when they were transfigured before him. The priesthood is everlasting—without beginning of days or end of years; without father, mother, etc. If there is no change of ordinances, there is no change of priesthood. Wherever the ordinances of the gospel are administered, there is the priesthood. … Christ is the Great High Priest; Adam next.’” (Doctrines of Salvation, vol. 2, p. 110.)
Because Christ was the first resurrected being, any prophet who had to perform earthly ordinances before his resurrection had to be preserved in the flesh. Thus, the Lord preserved Moses and Elijah in the flesh so they could confer the keys they held upon Peter, James, and John on the Mount of Transfiguration.
John the Beloved and the Three Nephites were translated and are still fulfilling responsibilities given to them. Enoch and his entire city were translated and caught up into heaven, to return to this earth at the second coming of Christ. There have also been others, such as Alma, who have not “tasted death.”
The Prophet Joseph Smith discussed the doctrine of translation, a power whereby men are preserved in their tangible, physical bodies, in the following words:
“Many have supposed that the doctrine of translation was a doctrine whereby men were taken immediately into the presence of God, and into an eternal fullness, but this is a mistaken idea. Their place of habitation is that of the terrestrial order, and a place prepared for such characters He held in reserve to be ministering angels unto many planets, and who as yet have not entered into so great a fullness as those who are resurrected from the dead.” (Documentary History of the Church, vol. 4, p. 210.)