Moroni clearly anticipates more Lamanite attacks, although it is not clear why. Certainly inspiration is a possible source. It is also possible that he keenly observed developments in the larger society and interpreted them correctly as a long-term trend, not a temporary aberration. During this time period, the foundations of the Maya Classic are being laid, characterized by an increased rate of militarism. Certainly Lamanite attacks become more frequent and larger in scale.
Given this understanding, Moroni continues to develop the fortifications that were so effective in discouraging the Lamanite attack at Ammonihah and throwing it back at Noah. The ridges of earth around the cities continue this already employed tactic, but placing timbers at the top of the mounds may have been an innovation. In any case, this type of defensive system is known for the Mesoamerican region. Even if Moroni were the originator, his innovations would have been widely copied once they proved their worth. It took the Lamanite army only one battle to copy Nephite armor (Alma 49:6). Of course, it is also possible that these innovations were developed in another region and enthusiastically adopted by Moroni, or that they were simply independent inventions.
Text: Why did Mormon chose to create a new chapter with this information? He has finished the story of a major character in a single chapter earlier; but this time, Moroni’s story extends across a chapter.
First, the year break forms a convenient point for completing one unit and moving to the next, although he has certainly covered several years in a single chapter before. I argue that a second, and more decisive, reason is that a different phase of the Lamanite wars begins here. The last chapter dealt with the Lamanite military invasion, but the Nephites were righteous. This chapter documents the rise of internal problems, with the number of the unrighteous increasing dramatically. That shift in the relationship of the people to Yahweh would, given Mormon’s compelling thesis in this narrative, make a chapter change appropriate.