The vision now begins the process of bringing together what were separate strands of God’s dealings with the children of Israel. For Nephi, this is confirmation that they will be gathered in to Israel, as God promised. The theme of their gathering will be important in Nephi’s later writings and also be an important theme for Jacob.
The first message is that while the Nephites are to be destroyed as a people, and that the remnant Lamanites would also fall to the coming Gentiles, the children of Lehi would not be utterly destroyed. Nephi sees that the Gentiles would neither destroy “the mixture of thy seed, which are among thy brethren,” nor “the seed of thy brethren.” Both Nephites and Lamanites will be preserved up to, and after, the time of these Gentiles upon the land.
This is important because the Gentiles will need Lehi’s seed (specifically the record they kept). Nephi notes that while the Gentiles have the gospel, they are missing plain and precious parts. Nephi will see that it is in the Lord’s mercy that the seed of Lehi will provide what the Gentiles lack.