Social: The Lamanites who were in rebellion were able to be in communication with one another such that they were able to flee together. This is important for understanding the nature of the rebellion. If it were isolated, it would have been much more difficult to have any uniform action among them. The idea that they were all able to move in somewhat unified intent and direction indicates that this group was already one that had a ready social boundary. In the Mesoamerican context, it was either a city-state, or one or more kin groups. The fact that they left to a particular location, and that they appointed a king (in the next verse) suggests that this was probably a set of kin groups that had rebelled against the king of the Lamanites and were attempting to declare their independence.
Geographic: The hill Onidah is called “the place of arms.” This is an interesting name and description because we have also seen a hill Onidah in the land about Antionum. It was the hill on which Alma preached to the farmers who had been excluded from Zoramite worship (Alma 32:4). That hill in the Nephite lands is not explicitly indicated as a “place of arms” but there is a possible correlation. John L. Sorenson suggests:
“In the classic pattern of the ambitious Nephite dissenter, this man went up to Nephi to egg on the king over the Lamanites to war against the Nephites (Alma 47:1). Many of the Lamanite folk, however, did not relish undertaking one more of the seemingly endless series of disastrous wars in which the Nephites always seemed to come out ahead. This time the majority of rebellious Lamanites from the vicinity of the city of Nephi simply fled to a nearby location called Onidah, “the place of arms.” Nearby was a Mount Antipas on top of which they assembled after arming themselves. Onidah clearly was in broken country no great distance from the capital city of Lehi-Nephi. In Mesoamerica, what constitutes a “place of arms” is obvious; it can hardly be anything other than an obsidian outcrop. This volcanic glass was the most convenient, most effective, and cheapest substance for manufacturing arms or any cutting tools. (Note that Alma 49:2 informs us that “arrows and stones” were the chief weapons of the Lamanites.) Trade in obsidian was the mainstay of commerce from earliest times. Some routes over which it moved extended as much as 700 miles.
It happens that one of the most extensive sources of this key material is the hilly zone called El Chayal, approximately sixteen miles northeast of Kaminaljuyu. Spots within the kilometers-wide obsidian exposures at El Chayal are virtually paved with waste chips, where cutting implements have been shaped by chipping. Obsidian from El Chayal was exported widely as early as Jaredite times. fn So the unhappy Lamanite folk, expecting to have to fight the king’s forces to keep from being pressed into military service, first went to Onidah, perhaps El Chayal, to arm themselves, then moved to the tactical safety of a mountain top.” (John L. Sorenson, An Ancient American Setting for the Book of Mormon [Salt Lake City and Provo: Deseret Book Co., Foundation for Ancient Research and Mormon Studies, 1985], 252.)