Nephi is not only predicting Christ’s appearance to the Nephites but notes that, at that future time, the law that governs their lives will change. The Nephites will keep the law of Moses until that time. Nephi therefore explains clearly not only the person of the Christ, but also the meaning of Christ in fulfilling the law of Moses. He looks forward to the day when the Messiah will provide a new law. It is interesting that it will be “the law which ye shall do.” Nephi expects that one must act according to the law. Now his people act under and according to the law of Moses. After the Messiah comes, they will act under and according to Christ’s law.
It is not clear whether this prophecy was widely available to the Nephites. Certainly they knew Lehi’s prophecy of the Savior’s birth in six hundred years because the unbelievers use that date to threaten the believers (3 Ne. 1:9). However, that prophecy is ascribed to Samuel the Lamanite, not Nephi (3 Ne. 1:4–6). Apparently, later Book of Mormon prophets did not explicitly repeat or attribute a knowledge of the coming of the Messiah to Nephi. Samuel’s recent prophecies may well have been better known, so not mentioning Nephi does not necessarily prove that the small plates had dropped out of public awareness, but their absence at least suggests that possibility. (See commentary accompanying Words of Mormon 1:3.)
Narrative: Nephi’s first recounting of this vision noted that the Messiah would appear to the Nephites (1 Ne. 12:6). This is not a copy of that vision, but another “original” telling of the vision Nephi received at that earlier point.