Doctrine and Covenants 77:6 [footnote]Doctrine and Covenants 77:6 – LDS.org[/footnote]
“Q. What are we to understand by the book which John saw, which was sealed on the back with seven seals?
A. We are to understand that it contains the revealed will, mysteries, and the works of God; the hidden things of his economy concerning this earth during the seven thousand years of its continuance, or its temporal existence.”
Crash Course:
Doctrine and Covenants 77:6 – LDS.org