Textual: We have a rather obvious shift in the narrative at this point. We have had a carefully crafted section that has a crafted ending. Now we have a moralizing text. There are two possible authors for this inserted moral. We may ascribe this section to Nephi, or we may see it as an addition by Mormon. While Mormon does not specifically identify himself, it is most reasonable to ascribe the text from here to the end of the chapter to Mormon.
First, we have the concluding statement of this unit; “Therefore for this time I make an end of my sayings.” Someone is declaring an end to their “sayings.” It is unlikely that it was Nephi, as Nephi still has the most marvelous story to tell. That story picks up in the next chapter, and the crafting of the rest of Nephi’s text suggests strongly that he would have continued directly into the appearance of the Savior.
Nevertheless, we have this inserted text, a trait that we have seen before in Mormon’s editorial process. All factors therefore point to Mormon as the author of this inserted section.
Mormon understands that the message of this part of Nephi’s record was the proof of the coming of the Atoning Messiah. Mormon emphasizes that message by noting that it fulfilled the scriptures as given by the prophets. Mormon is testifying that this is not only a witness by Nephi, but a witness by all of the prophets who had seen this event, long before it occurred.