Lucifer, who has no future, thus desperately tries to persuade men that they have no future either. He desires that all men might be miserable like unto himself. (2 Nephi 2:27) Misery likes company, especially ultimate misery.
The Prophet Joseph Smith taught, “God hath not revealed anything to Joseph, but what He will make known unto the Twelve, and even the least Saint may know all things as fast as he is able to bear them.”
Teachings of Presidents of the Church: Joseph Smith (2007), 268.