"Remarks on Slavery"
... inasmuch as we believe in the Bible, inasmuch as we believe in the ordinances of God, in the Priesthood and order and decrees of God, we must believe in slavery. This colored race have been subjected to severe curses, which they have in their families and their classes and in their various capacities brought upon themselves. And until the curse is removed by Him who placed it upon them, they must suffer under its consequences; I am not authorized to remove it. I am a firm believer in slavery.
... The African enjoys the right of receiving the first principles of the Gospel... of being baptized for the remission of sins and of receiving the Holy Ghost by the laying on of hands... But they cannot share in the Priesthood; they cannot bear rule; they cannot bear rule in any place until the curse is removed from them; they are a "servant of servants." ...
... there should be a law made to have the slaves serve their masters, because they are not capable of ruling themselves.
When the Lord God cursed old Cain, He said, "Until the last drop of Abel's blood receives the Priesthood, and enjoys the blessings of the same, Cain shall bear the curse;" then Cain is calculated to have his share next and not until then; consequently, I am firm in the belief that they ought to dwell in servitude.
[The Teachings of President Brigham Young, Vol. 3, 1852-1854. Fred Collier, ed. Collier's Publishing, 1987. 41-48, in The Complete Discourses of Brigham Young, Ed. Richard S. Van Wagoner, Smith-Pettit Foundation, Salt Lake City (2009), http://bit.ly/BY-discourses]