By these twenty-four plates, Alma means Ether’s record, discovered by the people of Limhi (Mosiah 8:7–9). Mosiah translated it, but Mormon did not include it in his text; Moroni adds the book of Ether at the end of his father’s record. Alma tells Helaman that it contains dangerous information but that the record must be preserved to testify to the danger of these “secret works of darkness.” In introducing Ether, Moroni emphasizes how the works of darkness (secret combinations) helped destroy the Jaredites, thus fulfilling Alma’s injunction about the record’s purpose.
Alma also mentions the “interpreters,” which Mosiah2 used in translating these same plates. Alma now explains their history among the Jaredites. (For more information on the interpreters’ transmission from the Jaredites to Mosiah, see commentary accompanying Mosiah 8:13; for more details on the “murders, and robbings, and their plunderings, and all their wickedness and abominations,” see commentary accompanying Alma 17:14, 50:21 and Helaman 6:17.)
Text: Ether’s record has two forms: the original twenty-four plates and Mosiah’s translation. Moroni, in introducing his abridgment of Ether, does not suggest that he is using the interpreters to make his own translation from the original twenty-four plates. He is most likely condensing Mosiah’s translation. Nevertheless, Alma tells Helaman that the “plates” must be preserved. But why should the interpreters accompany the text, given the existence of Mosiah’s translation? The interpreters would be useful only in making a second translation, but our received text of the Book of Mormon has no hint that those original plates were ever retranslated. Nor did Joseph Smith receive these plates—just Mormon’s editing with Moroni’s final additions (including the book of Ether) and the small plates of Nephi. I hypothesize that Helaman was charged with their preservation because they had the sanctity attached to a historic artifact whose contents, though unreadable except in translation, had come from a prophet. The interpreters are preserved, not for the plates of Ether but so that Moroni can deliver them to Joseph. Joseph would use them to translate the plates of Nephi as Mosiah had used them to translate the plates of Ether.
History: Mesoamerica has a long tradition of using oracle “stones,” or polished obsidian mirrors. These mirrors appear in art surviving from Olmec through Aztec times—virtually the entire cultural life of Mesoamerica. In these mirrors, the Mesoamerican shamans could see both past and present events.