3 Nephi 20: 14-15

3 Nephi 20: 14-15: 
 "And the Father hath commanded me that I should give unto you this land, for your inheritance. And I say unto you, that if the Gentiles do not repent after the blessing which they shall receive, after they have scattered my people—" 

Christ is speaking to a group of people and their descendants when making these remarks. The Father has commanded Christ to confirm to the Nephites they are given this land. "This land." So now the question of where Christ was while making these comments becomes important.

Where were they at the moment Christ spoke to them? That affects things, doesn't it? Was it Guatamala? Or the United States?

There are two ways of trying to determine the answer to this question.  One would be to study the internal content of the Book of Mormon and try to reconstruct a location based on the clues there. This has been done with varying results. The two leading works on the two leading theories have been referred to in this post. There is another theory that the area was in the Gulf of Mexico. The land was completely reformed, broken up, and altered as a result of the upheavals of the 3 Nephi destruction, and the land no longer appears as it did once. It is now underwater. You can work and justify a number of locations based on the content of the Book of Mormon.

The other way is to take other sources that presumably knew, and accept what they said about the location. I've already quoted from both Moroni and Joseph Smith about the location. Both have placed the events in the area now known as the United States. Moroni's description of the Book of Mormon, and its people, was as follows: "He said there was a book deposited, written upon gold plates, giving an account of the former inhabitants of this continent, and the source from whence they sprang."  (JS-H 1: 34.) I presume Moroni knew, and that Joseph had no reason to misstate what he said. It would appear that the continent referred to by Christ using the words, "this land" was North America. And the promise from the Father, made by covenant, was with "the former inhabitants of this continent."

So the remnant was (at the moment Christ was speaking to this audience, and confirmed this covenant of the Father) located in North America. This does not mean they weren't mobile and subsequently moved about. This does not mean they did not disburse and occupy other portions of the North and South American landmasses. This does not mean that other migrations of these people which scattered them elsewhere into the world have not occurred. Even if you confine everything to a North American venue for the entirety of the Book of Mormon account, there is still a gap between 400 a.d. when the narrative draws to a conclusion and the 1820's when the record comes to light again. Nothing closes that gap.

So if Moroni's comments to Joseph Smith can be trusted, then originally the people from whom the remnant came were people who lived on "this continent" at some time in history. 

The gentiles are mentioned again here. They are reminded of the blessings they have received. They are reminded they were given the responsibility of scattering the remnant and disciplining them for the remnant's failings. But, once the gentiles are blessed, once they have scattered the remnant and destroyed most of them (leaving only a remnant of what was here before), then the gentiles are warned. They must repent. Without repentance the fate of the gentiles will be a similar holocaust of destruction, scattering and treading down; leaving only a remnant of the gentiles still upon the land.

So the roles will reverse. At first, the gentiles dominate and the remnant recedes, at last the remnant will dominate and the gentiles recede.

The remnant's role and the gentiles' pride are interconnected with one another. It is for this reason, if no other, the subject of the remnant is important to know something about.

So, we continue.