Moroni wrote on the plates of Mormon an account of "the very things which the brother of Jared saw" in his great vision of the pre-earthly Jesus Christ. (Ether 4:4.) Concerning the importance of this vision, Moroni adds "there never were greater things made manifest than those which were made manifest unto the brother of Jared." (Ether 4:4.)
The Lord has indicated that the contents of the vision of the brother of Jared should not be revealed in a day when the people are wicked. Thus Moroni was commanded to write the account of the vision, but he was also commanded to "seal up the interpretation thereof . . . For the Lord said unto me: They shall not go forth unto the Gentiles until the day that they shall repent of their iniquity, and become clean before the Lord." (Ether 4:5, 6.)
It is not clear in the Book of Mormon exactly when the sealed record is to be revealed. However, some of the prior conditions that must exist are enumerated. For example, the Lord said that before the record is revealed the people must exercise faith in him "even as the brother of Jared did." (Ether 4:7.) Also, the Savior indicated that the people must "become sanctified" in him. (Ether 4:7.) Only then will the sealed portion of the records be revealed.