In addition to coming for a speech, the people are coming for a communal religious rite. The Law of Moses provides not only for individual worship, but community worship. Community acts both reinforce the purpose of the religious event, but they also help to cement the people through their communal participation.
“The typical New Year, like most festivals [prescribed in the Old Testament], evidently began with burn offerings of animals of ”the first year.“ ”In the seventh month, in the first day of the month…ye shall offer an offering made by fire unto the Lord“ (Leviticus 23:24-25)” (Szink, Terrence L. and John W. Welch. “An Ancient Israelite Festival Context.” In: King Benjamin’s Speech. FARMS, 1998 p. 164).
The sacrifices not only strengthen the supposition that this is a New Year ceremony, but also give us information about the scale of this communal rite: “And they also took of the firstlings of their flocks, that they might offer sacrifice and burnt offerings.” The critical question is “who are they”? We note that the verse follows directly the discussion of those who are coming to the ceremony, and not the priests who are in the town. It appears that the people are bringing animals to sacrifice. While there would be only a single animal sacrificed for each family group at the most, still there must have been a very large number of animals slated for sacrifice. Given the nature of Book of Mormon religion, it is probable that the meat of the sacrifices (at least a good portion of it) will be eaten by the people who are bringing the animal for sacrifice.