Mormon stresses this point because of the importance in his narrative of Lehi1’s foundational promise that the righteous will prosper and be protected. (See commentary accompanying 2 Nephi 1:9.) His own people, the Nephites, are becoming less righteous, which will lead to the inevitable destruction of the Nephite polity. As descendants of Lehi, however, the Lamanites can also be considered heirs to the same promise.
As I read this passage, however, Mormon is not referring to all Lamanites—who have always greatly outnumbered the Nephites—but to the Lamanites who have just been converted as a result of Nephi2 and Lehi4’s mission (Hel. 5:48–51). Corroborating evidence that Mormon had only this group in mind is the lack of a chapter break preceding this verse in the 1830 edition. The initial three hundred converts were ardent preachers who “convinced… the more part of the Lamanites” (Hel. 49–50). I also read “more part” as referring to a single city or closely connected group of cities—not all of those who might have been called Lamanites. Therefore, I see Mormon as taking editorial license to contrast the “universality” of Lamanite righteousness with the rising tide of Nephite unrighteousness.
Chronology: The sixty-second year of the reign of the judges is approximately 33 B.C. in this correlation.