Brigham Young second President and Prophet:
You see some classes of the human family that are black, uncouth, uncomely, disagreeable and low in their habits, wild and seemingly deprived of nearly all the blessings of the intelligence that is generally bestowed upon mankind. . . . Cain slew his brother. Cain might have been killed, and that would put a termination to that line of human beings. This was not to be, and the Lord put a mark upon him, which was the flat nose and black skin. Trace mankind down to after the flood, and then another cursed is pronounced upon the same race–that they should be the “servants of servants;” and they will be until that curse is removed; and the Abolitionists cannot help it, nor in the least alter that decree (Journal of Discourses, 7:290; emphasis added)
Shall I tell you the law of God in regard to the African race? If the white man who belongs to the chosen seed mixes his blood with the seed of Cain, the penalty, under the law of God, is death on the spot. This will always be (ibid., 10:110; emphasis added)
Brigham Young stated that his sermons (as cited above) are Scripture:
I have never yet preached a sermon and sent it out to the children of man, that they may not call Scripture (ibid., 13:95).
Does the Mormon church allow one prophet to overturn the teachings of another? And if so, then how can you trust or believe in the teachings of any of your prophets if they may change their teachings?