As with the note that the people were married, this is nearly non-information. We understood clearly after the visit of the Messiah that the Nephites as a religious people had shifted from the law of Moses to the gospel of Christ. The explicit notation of that fact here is not only repetitious, it is inconsequential. It tells us nothing new. Although Mormon has marked time, when he gets to the events of this “time,” they are non-specific. This reiterates to us that the events really are not the important information, but the structure of the information pre-eminently carries the message Mormon is trying to communicate.