Yahweh promises Nephi that his people’s words will come forth to his descendants at a particular time period. Those words will be part of the “marvelous work” (2 Ne. 29:1) that will bring the Gentiles to repentance and, hence, is part of their salvation and also the salvation of Nephi’s branch of the house of Israel. Significantly, the promise is made not only to Nephi, but also to Lehi, thus explicitly including both the Lamanites and the Nephites. The Book of Mormon will aid in the restoration of both lineages.
Reference: The distinctive description of the coming forth of the Book of Mormon is: “my words shall hiss forth.” It alludes to Isaiah 5:26: “And he will lift up an ensign to the nations from far, and will hiss unto them from the end of the earth: and, behold, they shall come with speed swiftly.” (See commentary accompanying 2 Nephi 15:26.) Nephi is not only using Isaiah’s imagery for its literary effect but also to place the Book of Mormon in the same context as Isaiah’s. Nephi’s association with Isaiah 5:26 symbolically equates the Book of Mormon with the ensign to the nations, matching the promise and context of Nephi’s passage.
He will again allude to the “ensign to the nations” when he quotes Isaiah (2 Ne. 30:9–15) but stops quoting just before the “ensign to the nations” passage, apparently relying on his reader to supply the continuation and the connection. Contextually, his quotations and reworkings of Isaiah point to the coming of the Book of Mormon as fulfilling the “ensign to the nations” prophecy; but for some reason, Nephi is content with implying, rather than making the connection concrete.