Moroni began his concluding chapter with an exhortation, then discussed the gifts of the Spirit, among which, by implication, was the Book of Mormon and the gift of understanding its truth, based on the recipient’s faith. He next, as part of sealing the plates, pronounced wo on unbelievers. Now, he pronounces the final aspect of the seal: his personal testimony that it is true. He evokes the scene at God’s judgment bar when God himself will accuse unbelievers of rejecting the truth.
Moroni speaks “like as one crying from the dead, yea, even as one speaking out of the dust.” Nephi had used a similar benediction at the end of his writing: “And now, my beloved brethren, all those who are of the house of Israel, and all ye ends of the earth, I speak unto you as the voice of one crying from the dust: Farewell until that great day shall come” (2 Ne. 33:13).
Both Nephi and Moroni are witnesses “from the dust” because their words speak to us now, even though their own day is long past. In both cases, this phrasing is borrowed from Isaiah 29:4: “And thou shalt be brought down, and shalt speak out of the ground, and thy speech shall be low out of the dust, and thy voice shall be, as of one that hath a familiar spirit, out of the ground, and thy speech shall whisper out of the dust.”
Nephi’s obvious mastery of Isaiah suggests that he employed the allusion intentionally and probably assumed that his readers would understand that he was fulfilling Isaiah’s prophecy. Verse 28, however, suggests that Moroni’s immediate reference is Nephi, not Isaiah.