The Book of Mormon says that its words would be revealed through a man authorized to “whisper” concerning the dead:
2 Nephi 26:14-18 – “But behold I prophesy unto you concerning the days when the Lord God shall bring these things forth unto the children of men…for they which shall be destroyed shall speak unto them out of the ground, and their speech shall be low out of the dust, and their voice shall be as one that hath a familiar spirit; for the Lord God will give unto him power, that he may whisper concerning them, even as it were out of the ground; and their speech shall whisper out of the dust.”
NSC attributes 2 Nephi 26 to Rigdon.
2 Nephi 26:14-18 – “But behold I prophesy unto you concerning the days when the Lord God shall bring these things forth unto the children of men…for they which shall be destroyed shall speak unto them out of the ground, and their speech shall be low out of the dust, and their voice shall be as one that hath a familiar spirit; for the Lord God will give unto him power, that he may whisper concerning them, even as it were out of the ground; and their speech shall whisper out of the dust.”
NSC attributes 2 Nephi 26 to Rigdon.