Even though the Gentiles will have a book that contains the words of the prophets, there will still be a need which will be fulfilled by the Nephite book, as will be shown later. The reason is that there have been plain and precious truths taken from the Old World book. What are those plain and precious things?
Nephi does not say specifically. However, we get a hint when he notes that what he writes on the small plates will be “the more plain and precious parts” of the revelations he has received (1 Nephi 19:3). In other words, we can see what Nephi considers most plain and precious by examining what he chooses to emphasize.
Just as did his father, Nephi emphasized the atoning mission of the Messiah. Both of those two prophets show by their emphasis what they thought to be missing from the teachings of their brethren in the Old World. We need not wonder about missing words or verses. It is a missing concept, and one that had at least begun to fade from Israelite religion in Lehi’s day.