3 Nephi 21:11

Therefore it shall come to pass, that whosoever will not believe in my words, which am Jesus Christ, which the Father shall cause him to bring forth unto the Gentiles, and shall give unto him power that he shall bring them forth unto the Gentiles, (it shall be done even as Moses said,) they shall be cut off from among my people which are of the covenant;

So whoever does not believe my words—and I am Jesus Christ—will be cut off from my people who have the promise. The Father will make him bring my words to the nations. The Father will give him power to bring them to the nations. It will happen just as Moses said.

Anyone who refuses to believe my words—I am Jesus Christ—which the Father will have this servant bring to the Gentiles, giving him power to do it, will be cut off from my covenant people. It will be just as Moses said.