NOTE: The Book of Moses was written by Joseph in 1830 and 1831, within a year or so after he published the Book of Mormon. It was a revision of some of the early chapters of Genesis. The following excerpt from the Book of Moses expresses the belief that black-skinned people were the cursed seed of Cain.

6 And again the Lord said unto me: Look; and I looked towards the north, and I beheld the people of Canaan, which dwelt in tents. 7 And the Lord said unto me: Prophesy; and I prophesied, saying: Behold the people of Canaan, which are numerous, shall go forth in battle array against the people of Shum, and shall slay them that they shall utterly be destroyed; and the people of Canaan shall divide themselves in the land, and the land shall be barren and unfruitful, and none other people shall dwell there but the people of Canaan; 8 For behold, the Lord shall curse the land with much heat, and the barrenness thereof shall go forth forever; and there was a blackness came upon all the children of Canaan, that they were despised among all people…. 20 And it came to pass that Enoch talked with the Lord; and he said unto the Lord: Surely Zion shall dwell in safety forever. But the Lord said unto Enoch: Zion have I blessed, but the residue of the people have I cursed. 21 And it came to pass that the Lord showed unto Enoch all the inhabitants of the earth; and he beheld, and lo, Zion, in process of time, was taken up into heaven. And the Lord said unto Enoch: Behold mine abode forever. 22 And Enoch also beheld the residue of the people which were the sons of Adam; and they were a mixture of all the seed of Adam save it was the seed of Cain, for the seed of Cain were black, and had not place among them. (Moses 7:6-8, 20-22)