Mormon rallies his army, achieves a series of victories, and drives the Lamanite/Gadiantons back until the Nephites have reclaimed their core territories. Mormon does not tell us how this happened but he does not attribute the victory to Yahweh, for “the strength of the Lord was not with us.” Apparently, no miracles occurred. A naturalistic explanation is that the Lamanite/Gadiantons attacking the fortified city of Shem had suffered unusually heavy casualties, prompting a retreat. Another reason may be that their supply lines had been over-extended.
Mormon does not mention Zarahemla as among “the lands of our inheritance.” The treaty terms (vv. 28–29) suggest that they were not able to move that far south.