Israel will be gathered when the Book of Mormon comes forth—The Gentiles will be established as a free people in America—They will be saved if they believe and obey; otherwise, they will be cut off and destroyed—Israel will build the New Jerusalem, and the lost tribes will return. About A.D. 34.
Read 3 Nephi 21 here: https://www.churchofjesuschrist.org/study/scriptures/bofm/3-ne/21?lang=eng