Joseph Fielding Smith explains the application of Moses 7 in missionary work among the "Canaanites."
Smith, Joseph Fielding, Jr. The Way to Perfection: Short Discourses on Gospel Themes Dedicated to All Who Are Interested in the Redemption of the Living and the Dead. 5th ed. (1931) (Salt Lake City, UT: Genealogical Society of Utah, 1945), 107.
It was well understood by the early elders of the Church that the mark which was placed on Cain and which his posterity inherited was the black skin. The Book of Moses informs us that Cain and his descendants were black. Enoch taught the Gospel among all the people everywhere, except the people of Canaan.