Joseph Fielding Smith
"There is strong presumptive evidence in the blessings given by Israel to his son Joseph, and his grandsons Ephraim and Manasseh, as recorded in Genesis, that they were to inherit a land far from Jerusalem and become a multitude of nations. Joseph was promised that his inheritance should be to the 'utmost bounds of the everlasting hills'; (Genesis 49:26.) that he was 'a fruitful bough by a well whose branches run over the wall.' (Genesis 49:22.) Moreover, he was to receive a greater inheritance than his progenitors, who were given the land of Palestine.
"The Book of Mormon is the record of the descendants of Joseph who were led across the 'great waters' to inherit this western land, which is designated as being choice above all other lands. Surely these blessings could not be realized in Palestine. Joseph and his sons did not become a multitude of nations there; the tribes of Ephraim and Manasseh did not receive a more wonderful inheritance in Palestine than any other of the tribes of Israel. There the chief honors were conferred first on Benjamin and then on Judah. Here in America all these promises were fulfilled when the descendants of Joseph possessed the land given as their inheritance.
"There are many references in the Bible to Zion, a land, or place, separate and distinct from Jerusalem. Such passages are found in the second chapter of Isaiah and the fourth chapter of Micah. It would be foolish to say that these references to Zion were to the hill in Jerusalem where David dwelt. Through modern revelation the Lord has made it known that the American continent is Zion. It is to be on this land that the city Zion, the New Jerusalem, shall be built." (A Book of Mormon Treasury: Selections from the Improvement Era, p. 191-2)
Joseph Fielding Smith
"With the translation of the Book of Mormon many of the descendants of Joseph were made known. Who could have made that great discovery without a revelation from the Lord? The Lamanites are of Israel. Lehi was a descendant of Manasseh. We are informed that Ishmael, whose children joined the family of Lehi, was of Ephraim. In this way children belonging to these two tribes were planted in America. It is true that others also came, and it is just possible that the Lord, remembering his promise to Joseph, sent with the Mulekites others of the tribes of Joseph. At any rate, this land was given to them as their everlasting inheritance. They have inherited it in the past. They will do so more fully in the future.
"We are told that there was a prophecy in the destruction of the coat of many colors worn by Joseph. (See Gen. 37:31-35.) Part of it was preserved, and Jacob, before his death, prophesied that as a remnant of the coat was preserved so should a remnant of Joseph's posterity be preserved: 'And he said, Even as this remnant of garment of my son's hath been preserved, so shall a remnant of the seed of my son be preserved by the hand of God, and be taken unto himself, while the remainder of the seed of Joseph shall perish, even as the remnant of his garment.' (Alma 46:24.)
"That remnant now found among the Lamanites shall eventually partake of the blessings of the gospel. They shall unite with the remnant which is being gathered from among the nations and they shall be blessed of the Lord forever." (The Way to Perfection, p. 121)