Social: This verse provides an important datum concerning the nature of the Nephite army. After their battle, they “all returned to their lands, and to their houses, and their wives, and their children.” They did not return to “the fort,” or “their base.” They went home. It appears that even at this stage in Nephite society there is no standing army.
This absence of an official standing army continued to be the practice in Mesoamerica up to the time of the arrival of the Spaniards. Even the feared Mexica (commonly known as Aztec) war machine was composed primarily of commoners who were called up as needed. (Hassig, Ross. Aztec Warfare. University of Oklahoma Press, 1988, pp. 53-54)
This lack of a standing army has multiple important implications for the nature of Nephite society. The first, and most obvious, is that the ability of the Nephites to respond to military threats required the ability to predict with sufficient advanced the time of arrival of an enemy army. Thus we find in the Book of Mormon frequent mention of scouts or lookouts.
Second, the lack of a standing army highlights the inability of Nephite political leaders to enforce their will on the people. The book of Mormon never mentions a police force, and the “voice of the people” operates as the means of enforcing decisions, not force of arms.
When there are dissenters, the dissent is allowed (or the dissenters physically remove themselves) without any attempt at physical control over the dissenters. In many ways, the contention cycles so apparent in Nephite society in their sojourn in Zarahemla are allowed by the lack of a means of enforcing a single mode of thought on the people. From a sociological standpoint, the lack of a standing army and a cycle of dissent are two factors that fit together. Had there been an indication of a standing army in the text, the extremely short cycles of political instability would be anomalous.
The last facet of this popular army that is important to recognize is that the necessities of food production tend to make this a seasonal activity:
“In civilizations at such a level of technological development, armies were formed of nonprofessional militia. For example, Alma 44:23 says, “The armies of the Nephites … returned and came to their houses and their lands.” The demand for manpower to carry on agriculture provided the most stringent limit on maintaining armies. The husbandry of those times simply could not provide sufficient reliable surplus to feed many soldiers who were not themselves involved in the seasonal work.
When an army did have to be kept in battle readiness, an added burden fell on the men who were still cultivating; thus the pacifist people of Ammon were obliged to exchange the products of their labor, “a large portion of their substance to support our armies,” in exchange for protection by Nephite soldiers (Alma 43:13). But unavoidably, most of those serving in the army had to meet farming’s demands during part of the year.
Another seasonal consideration was the weather. Anywhere in the tropics, rain characterizes approximately half the year—the same season when the crops are growing—with resulting muddy trails and swollen streams to cross. In all likelihood, the only time when Alma and his forces could have waded across the river Sidon, fighting as they went (see Alma 2:27), would have been in the drier part of the year. Furthermore, had armies been fighting during the rains, they would have suffered significantly while traveling, camping, or fighting, for that time can be uncomfortably cool and unhealthy. Typically the Lamanites traveled virtually naked to reach the Nephites (see Enos 1:20; Alma 3:5; 43:20, 37). They would not have done so had protecting themselves against rain and cold been a concern. On the contrary, heat-caused fatigue was mentioned as a problem in the lowlands (see Alma 51:33; cf. 62:35). So the scripture confirms logic and observations about the timing of warfare in tropical lands—the rainy season ruled out major campaigns, which took place in the dry season instead.
Of course, there could be exceptions. Regions varied in climate; certain places and times would have permitted at least limited fighting other than at the normal dry time, although we must assume that planned major campaigns had to follow the general rule. Sorenson, John L. “Seasonality of Warfare in the Book of Mormon and in Mesoamerica.” In: Warfare in the Book of Mormon. FARMS, 1990, pp 447-8)