In Alma 53, Mormon spends half of the chapter describing the things Captain Moroni did after the battle and the second half introducing us to background information about the stripling warriors. That second half is full of interest to us, but I think the first half is instructive too because it shows there is more for an army to do than just fight.
Mormon probably found these details worth recording because of the great positive contrast they represented to the depraved Nephite armies of HIS day who tortured, raped, and ate prisoners, who stole food from widows and orphans, who were without order or mercy, who did nothing to alleviate, but rather augmented the suffering of women and children (Moroni 9). Undoubtedly Mormon wished his own armies could be like Captain Moroni's.
In Alma 53, Mormon notes that Captain Moroni and his armies
• Had the Lamanites bury the dead (cleaning up battle mess)
• Took care of the prisoners and put them someplace safe, even though the place wasn’t ideal at first.
• Gave the prisoners something important to do (fortify) and watched over them while they did it (prisoners contributed to war effort)
• Continued fortifying and preparing for war
• Delivered their wives and children from famine and affliction
• Provided food for the armies
I think this is a great example of the principle “clean up after yourself.” We see the divine roles of manhood at work--providing and protecting. We see charity in action, even toward prisoners of war. We see that the army of destruction can become an army of construction.