This land, the land of promise, is a “promise” given by covenant that would extend from one generation to the next, forever, to Lehi and his family. He obtained it, for themselves and his posterity as an inheritance from the Lord, others also. Lehi reveals the Lord would lead others here from “other countries” the promises associated with this land in particular also belong to them.
“….we have obtained a land of promise, a land which is choice above all other lands; a land which the Lord God hath covenanted with me should be a land for the inheritance of my seed. Yea, the Lord hath covenanted this land unto me, and to my children forever, and also all those who should be led out of other countries by the hand of the Lord.”
While it is apparent others came here at different periods of time, and by different means, some of those populations likely mingled their seed with the descendants of Lehi, Ishmael and his family, some arriving before Lehi that we currently do not have a record of, other than the Jaredites to which we only have a small portion of their record, and also others who came after Lehi who we presently have no records of, though we do have oral traditions from some of the North American Tribes that have been passed down from whence and how their ancestors came to be upon this land.
The North American Indians are the remnant of the House of Jacob or the Jews, not directly as those we consider the Jew who are found in Israel and other places in the world today, but of Joseph (Ephraim/Manasseh) – descendants of the same Joseph who was sold into Egypt, and also those who were called the people of Zarahemla, who likewise came from Jerusalem in the days of King Zedekiah, being descendants of Mulek the youngest son of Zedekiah who was most likely away in Egypt when Jerusalem fell , his father and older brothers being killed, here, we see another remnant of the Jew who gathered in North America, arriving shortly after Lehi and his family, these are of the tribe of Judah to whom King Mosiah and those with him being descendants of Joseph, and Lehi and his sons Nephi, Jacob and Joseph who came to live with them. These two branches came together here on the North American Continent almost 300 years after their fathers had fled Jerusalem, approximately 300 B.C.E., it is their descendant who carry in their blood these two primary lineages, both Joseph (Ephraim/Manasseh) and Judah. These are the remnant of Jacob who are identified by the Lord as the “Nephites, and the Jacobites, and the Josephites, and the Zoramites,” and “the Lamanites, and the Lemuelites, and the Ishmaelites”. These are the primary ancestors of the North American Indians, the broken branch of the House of Jacob, the remnant Jew, the Lamanite.
The Lord decreed in their wickedness that the Lamanites would be scattered, that the Gentiles would come upon this land and nearly destroy the mixture of their seed– i.e. meaning marriage, mixing of their people with other peoples – becoming nearly lost and unidentifiable or undistinguishable culturally, becoming genetically wiped out or genetic genocide, that they would be scourged and scattered from their lands, by the hand of the Gentiles, what had been done to the Nephites by them, because of their wickedness, was turned upon their own heads by the Gentiles for their rejection of Christ and His gospel, and likewise the Lamanites shall turn it upon the heads of the Gentiles because of their wickedness and rejection of the fullness of the gospel.
The Gentiles came from Europe and other parts of the world, starting with Christopher Columbus marking the great gentile migration to this land, their arrival would bring plagues upon the Indian and scourge many, nearly destroying them, the Gentiles decimated their culture and left them in literal ruin, through wars, and treaties like the Indian Treaty and Removal Act of 1830 this being the final blow to this people as a whole. Yet the Lord promised to their fathers by covenant, that they would not completely be destroyed, but that He would remember them and the covenants which He has made with their fathers, and that this people would be restored temporally and spiritually, becoming again a righteous branch unto the Lord, forever.
Before this day could come, the day of the Gentiles must needs come and all be fulfilled that is written and prophesied about them, and all that had been prophesied and written concerning the destruction and scattering of the Lamanites by the hand of the Gentiles, likewise needed to be fulfilled, before they could be restored.
April 6, 1845 in a Proclamation of the Twelve, states in part: “For be it known unto them [the Jew] that we now hold the keys of the priesthood and kingdom which is soon to be restored unto them.”
“He has said that he will not come in his glory and destroy the wicked, till these warnings were given and these preparations were made for his reception.-And we know it.”
The Priesthood, the Gospel, Scepter of Power and Righteousness is to be GIVEN back to them, this is what RESTORED means, it is to return something that rightfully belongs to them, to be made whole again, the Gentiles having rejected the fullness, forfeited there claim and rights to lead the House of Israel and the Hosts of Heaven. If they repent, they may assist the remnant of Jacob, the Indians, in building up Zion and this great work.
It is by covenant and a promise that the remnant of Jacob, be the ones to build up and finish the work started by the Gentiles, it is written and prophesied they will build Zion. Those who will gather from the House of Israel to help, and the Gentiles who repent – will assist in finishing the work with them.
 2 Nephi 1:5
 2 Nephi 1:5
 Omni 1:20-21 & Ether 2:6-7
 D&C 3:17-18
 Mormon 5:20
 1 Nephi 13:10
 1 Nephi 13:14
 3 Nephi 21:12
 3 Nephi 16:10
 Helaman 15:11-12
 2 Nephi 3:21
 2 Nephi 10:7 & 3 Nephi 16:11-12
 2 Nephi 9:53
 3 Nephi 21:23