That is rather harsh isn’t it? However, saying that Brigham Young was a false prophet is more than just anti-Mormon bias. What is the test of a prophet?
“But a prophet who presumes to speak in my name anything I have not commanded him to say, or a prophet who speaks in the name of other gods, must be put to death.” You may say to yourselves, “How can we know when a message has not been spoken by the LORD?” If what a prophet proclaims in the name of the LORD does not take place or come true, that is a message the LORD has not spoken. That prophet has spoken presumptuously. Do not be afraid of him.” (Deuteronomy 18:20–22 NIV)
It is pretty simple, if a prophet prophesies something and they are wrong, they are a false prophet. However, we need something more precise than just a claim that Mormonism is wrong and the result of false prophecy. Here is a specific claim:
“Why are so many of the inhabitants of the earth cursed with a sin of blackness? It comes in consequence of their fathers rejecting the power of the Holy Priesthood, and the law of God. They will go down to death. And when all the rest of the children have received their blessings in the Holy Priesthood, then that curse will be removed from the seed of Cain, and they will then come up and possess the priesthood, and receive all the blessings which we now are entitled to. The volition of the creature is free; this is a law of their existence, and the Lord cannot violate his own law; were he to do that, he would cease to be God” (Brigham Young, August 19, 1866, Journal of Discourses11:272).
Brigham Young makes it very clear that blacks cannot receive the priesthood until everyone else has received it. Since LDS still ordain people to the priesthood, presumably that time has not yet come. And yet this is what happened in 1978:
June 8, 1978
To all general and local priesthood officers of The Church of Jesus Christ of Latter-day Saints throughout the world:
As we have witnessed the expansion of the work of the Lord over the earth, we have been grateful that people of many nations have responded to the message of the restored gospel, and have joined the Church in ever-increasing numbers. This, in turn, has inspired us with a desire to extend to every worthy member of the Church all of the privileges and blessings which the gospel affords.
Aware of the promises made by the prophets and presidents of the Church who have preceded us that at some time, in God’s eternal plan, all of our brethren who are worthy may receive the priesthood, and witnessing the faithfulness of those from whom the priesthood has been withheld, we have pleaded long and earnestly in behalf of these, our faithful brethren, spending many hours in the Upper Room of the Temple supplicating the Lord for divine guidance.
He has heard our prayers, and by revelation has confirmed that the long-promised day has come when every faithful, worthy man in the Church may receive the holy priesthood, with power to exercise its divine authority, and enjoy with his loved ones every blessing that flows therefrom, including the blessings of the temple.
This declaration opened up the priesthood to all Mormons, regardless of race. This leaves us with two options: Brigham Young was mistaken or God was mistaken. If Brigham Young was wrong in this, he can only be understood as a false prophet.
For more information, go to Mormon Research Ministry.