Mormon now turns to a dramatic story involving the people of Ammon. He begins this story having set up the problem of the Nephites. The eastern border that is closer to the land of Jershon is now secured. The people of Ammon are once again in fairly well protected Nephite territory. The military situation in the west is now desperate, and Moroni will certainly have to leave troops to guard the eastern borders. The loss of men in the war, and the continued need to divide his resources is depleting the numbers of Moroni’s available army right when he will need all of his forces to fight off the incursions on the western front. This is the military situation that frames the story of the people of Ammon at this time.
The first salient piece of information of which Mormon reminds us is that the people of Ammon were promised protection by the Nephites. They have received that protection, and are under an oath that binds the Nephite government.