Aaron begins to teach from the scriptures, not only because they contain prophetic explanations of these principles but because the Nehorites accept some scriptures. (See “Excursus: Religion of the Nehors,” following Alma 1.) Possibly they considered only the brass plates scripture, dismissing the writings of Nephite prophets as among those the “fathers” accepted but without knowing of “which they spake.” Aaron begins with scriptures they accept to show in them the doctrines that they reject. As a result, the people do not repent; rather they become angry and unleash a verbal assault on Aaron.
Redaction: Typically, Mormon quotes speeches from his source plates if he considers the subject important to his message. But here, he summarizes Aaron’s discourse in a single verse (v. 9). Was Aaron’s discourse missing from the source? If not, why did Mormon he condense it so dramatically? Of course, we do not have the source plates for comparison, but I argue that the source contained a full (or at least fuller) account. First, it was important in Mormon’s source that the heckler was an Amalekite. That identification must have been a more important detail in the source. The conversation between the two takes the form we expect of recorded dialogue, and the similarity to the issues and format recorded in the confrontation between Zeezrom and Alma and Amulek also suggests that Aaron’s experience appeared in his own record.
However, the strongest evidence that Mormon made an editorial choice to summarize comes when he quotes Aaron’s much longer discourse to Lamoni’s father. Since Ammon was not present, this speech must have come from Aaron’s record. Having a complete record of one speech but not the other is inconsistent.
But why would Mormon omit Aaron’s sermon to the Amalekite? First, it is redundant information covered by Alma and Amulek. Second, Mormon is obviously more interested in the heightened social drama of Aaron’s appearance before Lamoni’s father.