Moroni turns his attention to his eastern border. This was a potentially weak area. We have seen this area as source of potential worry in the story of the Zoramites. In particular, we are told in Alma 31:3 that this wilderness on the east was “full of the Lamanites.” In spite of being “full of the Lamanites” it does not appear to have any significant Lamanite cities. When Corianton goes to the harlot Isabel, the text does not reference a city, but rather the “land of Siron” (Alma 39:3).
This area does not appear to have been a threat to the land of Zarahemla in the past, with the exception of the Lamanite invasion occasioned by the Zoramite defection. However, that experience had shown the area as vulnerable. Moroni not only defends the cities, but in this case removes the Lamanites from the eastern wilderness. This move took away people who had not been particularly belligerent, but who might at least be sympathetic to the Lamanites, and therefore a source of supply. By removing them, Moroni denied any Lamanite sympathizers in that area, thus strengthening the geographic integrity of the land of Zarahemla.