The Lord has a design in preserving and bringing forth the Book of Mormon. He has a design in raising up chosen prophets to convey His word to the honest at heart. Nephi has learned from his father much detail concerning the latter’s visions about the course of Israel’s history and future destiny. Nephi himself, after much prayer and fasting, is privileged to partake of the heavenly vision firsthand (see 2 Nephi 12–14). Thus he is schooled of the Lord in the design of heaven and in the essence of the prophecies of Isaiah (who saw in vision the unfolding of the very same covenant plan) and can speak with authority about the nature and implications of Isaiah’s words. In particular, Nephi clarifies Isaiah Chapter 29 concerning the mysterious sealed book—a reference that has seemed to the world to be fairly cryptic. Nephi makes clear that this sealed book is none other than the record that he himself has initiated at God’s command. With prophetic eye he looks forward to a time when this very record, extended and completed by a series of inspired prophets and compilers over the ages, will be brought forth “by the power of God” (Mormon 8:16) to a latter-day world hungry for the fulness of the everlasting gospel of Jesus Christ.
It would appear that one of the principal reasons the Lord directs the recording of so many of Isaiah’s words in the Book of Mormon is so that the inspired commentary of Nephi concerning these words can be placed in juxtaposition to the original text. This allows the inspired commentary to shed additional light and truth on important themes “according to my plainness; in the which I know that no man can err” (2 Nephi 25:7).