After texts condemning the unrepentant Gentiles, the Savior discusses the fate of the repentant Gentiles. If the repent and believe on the Messiah, the church will be established among them. The Nephites would have understood “church” in their own context as their organization. They would have understood, however, that it was an organization of believers in the context of a population of unbelievers. Thus while the specifics of organization might have been different, they certainly had a sufficient conception of what would be established among the Gentiles. Of course the modern perspective tells us that this is the restoration of the Church and the organization of the Church of Jesus Christ of Latter-day Saints.
These Gentiles who belong to the church are adopted into the covenant of Abraham, and become inheritors of the promise of the land. Thus the promise that this land would be for the inheritance of the house of Israel has partial fulfillment in the Gentile believers who are adopted into the House of Israel.
In the modern patriarchal blessings we receive, our spiritual lineage is declared, indicating our adoption into these blessings.
“It is the office and calling of a patriarch in giving a patriarchal blessing to identify, by the Spirit of revelation, the blood lineage of those whom he blesses. President Joseph Fielding Smith taught: “A patriarch giving a blessing has the right of inspiration to declare the literal descent of the person receiving the blessing; he does not have authority to assign that individual to any tribe. Through the waters of baptism and the priesthood, Church members become heirs of Abraham with all the rights belonging to the children of Abraham through their faithfulness” (Doctrines of Salvation, 3:171).
The promises given to Abraham are not figurative. He was expressly told they were to extend to his “literal seed, or the seed of the body” (Abr. 2:11). If those of the Bible-believing world properly understood the promises given to Abraham, they would know that the blessings of the priesthood are essential to salvation and that the right to hold the priesthood was given to Abraham and his posterity. It is his seed that are to bear the message of the gospel to all the ends of the earth. Missionaries are expected to have received their patriarchal blessing before they begin their missions. Thus they will have a revealed confirmation that they are of the lineage that has a rightful claim to the priesthood and the attendant responsibility to declare the message of salvation to the ends of the earth.” (Joseph Fielding McConkie, Answers: Straightforward Answers to Tough Gospel Questions [Salt Lake City: Deseret Book Co., 1998], 183 - 184.)