According to Richard Rust, the skillful use of repetition in the Book of Mormon as a principle of reinforcement and witness can be appreciated by close examination of various narrative threads woven by Nephi, Mormon, and Moroni. An excellent example of this repetition can be found in 1 Nephi 5, starting with Nephi's reference to Sariah's lament:
For she [Sariah] had supposed that we had perished in the wilderness; and she also had complained against my father, telling him that he was a visionary man; saying:
(1) Behold thou has led us forth from the land of our inheritance, and
(2) my sons are no more, and
(3) we perish in the wilderness. (1 Nephi 5:2, emphasis added)
In Nephi's narrative, Sariah's worries are counterbalanced six verses later by her three-part witness uttered at the return of her sons:
Now (1) I know of a surety that the Lord hath commanded my husband to flee into the wilderness; yea, and
(2) I also know of a surety that the Lord hath protected my sons, and delivered them out of the hands of Laban, and
(3) given them power whereby they could accomplish the thing which the Lord hath commanded them. (1 Nephi 5:8)
The reader should note that Sariah's final statement reinforces and echoes Nephi's initial covenant commitment: "I will go and do the things which the Lord hath commanded, for I know that the Lord giveth no commandment unto the children of men, save he shall prepare a way for them that they may accomplish the thing which he commandeth them." (1 Nephi 3:7)
With this covenant relationship in mind, we now view Lehi and Nephi (and Sariah) as they rejoice that they had:
(1) kept the commandments,
(2) obtained from Laban the records which the Lord had commanded, and
(3) now could preserve the commandments of the Lord unto their children (1 Nephi 5:20-21)
[Richard D. Rust, "Recurrence in Book of Mormon Narratives," in Journal of Book of Mormon Studies, Vol. 3, Num. 1 (Spring 1994), pp. 46-47] [See the commentary on 1 Nephi 3:7; 1 Nephi 5:4; 1 Nephi 5:8; 3 Nephi 14:23]