Textual: Note how Mormon weaves his theme into the history of this particular conflict. Mormon is showing how the Nephites’ righteousness directly alters their protection under the foundational promise. He first notes that the loss of land was directly due to their unrighteousness. Now he notes that there are those who preach repentance to the people, and that there is some return to God, and this return is sufficient that Moronihah is able to recapture half of the lands.
With this statement Mormon does two things. First he strengthens his moral argument that the fate of the Nephites is tied to their righteousness through the implicit evocation of Lehi’s promise. However, he also leaves us the presaged continuation of difficulties by emphasizing that Moronihah was only able to regain half of their possessions. While this is historically true, it is also morally true. The repentance was not complete, as events will continue to show. Thus Mormon can have an explanation for the loss of land, for the regaining of the land, but the eventual destruction of the Nephite polity that will occur in not too many years.