In three verses, Mormon mentions the “fifteenth year” of the reign of the judges three times. We saw very little of the counts of the years in the material Mormon selected from Alma’s personal record. However, the dating by years is a hallmark of the organizational structure of the large plates, beginning with the book of Alma. Nevertheless, stating the fifteenth year this frequently is unusual.
Mormon is combining information from two records, Alma’s personal record and the large plates. He is also inserting his own opinions as well as copying Alma’s statements. What we are seeing in these verses appears to be a transition from Mormon using the large plates to a return to copying from Alma’s personal record.
What we will see is more than a repetition of the year, but a repetition of the aftermath of the terrible war. First, Mormon gave his reaction. Now Mormon will return to Alma’s reaction. Although the dating by years is not a feature of Alma’s personal record, Alma does mention the years from time to time. In this case, we are probably seeing the shift in Mormon’s use of the sources between verses 8 and 9.
The story of the sons of Mosiah began in the first year of the reign of the judges, and Mormon has been telling a story that occurred in Lamanite lands and according to a record that wasn’t part of the large plates. Here, he reconnects the story of the sons of Mosiah not only with their meeting with Alma, but with what has happened in the time that they were gone. Not only were there Lamanite incursions that Mormon somewhat awkwardly mentioned in Alma 25:13 and again in Alma 27:1, but here Mormon indicates that there were many wars in those fifteen years. It appears that Mormon had also attempted to include some of this information from the large plates as he was discussing the story of the Anti-Nephi-Lehies, but did so in an incomplete manner.