3 Nephi 16:4

And I command you that ye shall write these sayings, after that I am gone, that if it so be that my people at Jerusalem, they which have seen me, and been with me in my ministry, do not ask the Father in my name, that they may receive a knowledge of you by the Holy Ghost, and also of the other tribes which they know not of, that these sayings which ye shall write, shall be kept, and shall be manifested unto the Gentiles, that through the fulness of the Gentiles, the remnant of their seed which shall be scattered forth upon the face of the earth, because of their unbelief, may be brought in, or may be brought to a knowledge of me, their Redeemer.

I tell you to write down these words after I leave. My people in Jerusalem have seen me. They have been with me while I taught. If they do not ask the Father in my name to learn about you through the Holy Spirit, and about the other tribes they do not know, then these words you write will be kept. They will be shown to the non-Jewish people. Through the non-Jewish people, the rest of your family who are scattered across the earth because of their unbelief can be brought back. They can learn about me, their Savior.

Now, write down what I’m telling you. After I’m gone, my people in Jerusalem—the ones who saw me and walked with me—may not ask the Father to reveal you to them through the Holy Spirit. They may not ask about the other tribes they don’t know about. So these words you’re writing will be preserved and given to the Gentiles. Through the Gentiles, the scattered descendants of Israel—scattered because of their unbelief—will be brought back to know me, their Redeemer.