According to Terrance Szink, the book of Third Nephi begins with an interesting staement about Nephi the son of Helaman. Mormon wrote that he "departed out of the land and whither he went, no man knoweth" (3 Nephi 1:3) and that he "did not return to the land of Zarahemla, and could nowhere be found in all the land" (3 Nephi 2:9). This is reminiscent of a similar passage about Nephi's great-grandfather Alma the younger: "He departed out of the land of Zarahemla . . . and it came to pass that he was never heard of more; as to his death or burial we know not of" (Alma 45:18). Even more intriguing is the fact that other similiarities are noted in the text between the lives of Alma and Nephi. Among other things
(1) both were judges (Nephi-Helaman 3:37; Alma-Mosiah 29:42-44),
(2) both gave up their judgeship to devote more time to service in the church (Nephi-Helaman 5:1-4; Alma-Alma 4:20)
(3) both were thrown into prison because of their preachings but were miraculously delivered (Nephi-Helaman 5:21-44; Alma-Alma 14:22-28),
(4) both were granted great power (Nephi-Helaman 10:5-10; Alma-Alma 8:31), and
(5) weary with the wickedness of their people, both wished for something different than the circumstances in which they found themselves: Nephi wanted to live in the days when Lehi and his family left Jerusalem (Helaman 7:7), and Alma wanted to speak with the voice of an angel (Alma 29:1-3).
[Terrence L. Szink, "A Just and a True Record," in Studies in Scripture: Book of Mormon, Part 2, pp. 125, 136]