Although Joseph was the 11th of 12 sons born to Jacob, he was the one who inherited the birthright. Elder Joseph Fielding Smith explained: "Because of his faithfulness and integrity, Joseph received greater blessings than the progenitors of Jacob and was rewarded with the land of Zion.
"His brothers, with malicious intent, separated him and cast him out from among them. The Lord, in rewarding him, separated him from his brothers - the other tribes of Israel - and gave him an inheritance in a land that is choice above all other lands, which, we have learned from the Book of Mormon and modern revelation, is America." (Doctrines of Salvation 3:68.)In The Way to Perfection, Elder Smith wrote:
"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."