It is highly significant that for several centuries the Nephite leaders labored mightily to preserve the land northward as a refuge in case they were forced out of the land southward.
Although this account is abridged from the record of Alma, Mormon inserts an occasional editorial comments such as the next verse where he says:
“Therefore the Lamanites could have no more possessions only in the land of Nephi, and the wilderness round about. Now this was wisdom in the Nephites -- as the Lamanites were an enemy to them, they would not suffer their afflictions on every hand, and also that they might have a country whither they might flee, according to their desires. And now I, after having said this, return again to the account of Ammon and Aaron, Omner and Himni, and their brethren.”