Ether 4

 After the record of the Brother of Jared concerning his revelations released after the coming of the Savior, Moroni tells us - 

"...the Lord hath commanded me to write them; and I have written them. And he commanded me that I should seal them up; and he also hath commanded that I should seal up the interpretation thereof; wherefore I have sealed up the interpreters, according to the commandment of the Lord.

6 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.

7 And in that day that they shall exercise faith in me, saith the Lord, even as the brother of Jared did, that they may become sanctified in me, then will I manifest unto them the things which the brother of Jared saw, even to the unfolding unto them all my revelations, saith Jesus Christ, the Son of God, the Father of the heavens and of the earth, and all things that in them are."  (Ether 4:5–7)

This suggests that what is had in the Bible and The Book of Mormon in not complete and that we still have great need for much more. I've even wondered if temple ordinances and covenants are included in the sealed portion.