As with the previous time that a testificatory amen caused Nephi to end a chapter, the story he was telling had not ended. He ended the chapter testifying that he had taught his brothers truth, but he didn’t finish telling what effect his teaching had. Of course, we expect that it was effective, and these verses show that indeed it was.
Nephi had begun explaining the general symbols of Lehi’s vision, but the ending pointed directly at Laman and Lemuel. They got the message. Nephi exhorted them to keep the commandments, and they humbled themselves to repentance. Again. Of course, we who have read the whole story know that this will be temporary. However, that is also the lesson for us, as readers. We too may be humbled, but the task of the gospel is not just the ability to be humbled and repent, but to endure in that repentance until the end. That is the part that Laman and Lemuel will miss.
We know that this story has now ended because Nephi states that: “all these things were said and done as my father dwelt in a tent.” As we have seen before, Nephi uses the tent of his father as transition points in stories inside of chapters. He is now ready to begin a new story.