Hugh Nibley
"The next verse is very revealing. 'But it came to pass that whatsoever lands we had passed by, and the inhabitants thereof were not gathered in, were destroyed by the Lamanites, and their towns, and villages, and cities were burned with fire' (Mormon 5:5). Here you have a clear picture of Nephite society. Separate 'lands' living their own lives, now in this last crisis terribly reluctant to move and join the swelling host in the retreat to the north. Those who refused to pull up stakes were one by one completely wiped out by the Lamanites. This was no planned migration but a forced evacuation, like dozens of such we read about in the grim and terrible times of the 'Invasion of the Barbarians' that destroyed the classic civilizations of the Old World. In this case Mormon's people were only part of the general and gradual evacuation of the whole land. The Nephites lost a general battle in the next year and resumed their headlong flight, 'and those whose flight was swifter than the Lamanites' did escape,' says Mormon, not mincing words, while the rest 'were swept down and destroyed' (Mormon 5:7). The fitful but continual falling back of the Nephites towards the north, which had now been going on for fifty-three years, became something like a rout, with speed the only hope of survival." (An Approach to the Book of Mormon, p. 267)