Mormon may have been young, but he was not ineffective. The Nephites had suffered greatly, some of which was due to the fact that the Nephite armies had fled rather than engaged their enemies. In this particular engagement, three years into the war, Mormon finally notes a Nephite victory.
Along with the victory, Mormon notes that the Nephites finally “began to repent of their iniquity.” Nevertheless, “there began to be a mourning and a lamentation in all the land.” Even with repentance beginning, there was much sorrow for all of the loss of life and lands. Sadly, even their repentance was perhaps too little, and too late.