"I am a Prophet of God in this dispensation. I carry on the work that began with Joseph Smith. I led the Saints to the barren Salt Lake Valley and it is where we built Zion, even though Joseph Smith taught the Savior would return in Jackson County Missouri. Monogamous marriage is not the order of heaven, for it is only through polygamy that a man may achieve exaltation. The government should stay out of the lives of the Saints and let us worship and practice our religion according to the dictates of our own conscience. If there ever comes a day when the Saints interfere with the rights of others to live as they see fit, you can know with assurance that the Church is no longer led by a Prophet, but a mere man. The doctrines of this Church are eternal, for they were ordained before the world was and any man who changes these doctrines such as the temple ceremony, or the man who abandons polygamy, or allows blacks the Priesthood of God, is a fallen prophet. I am Brother Brigham. And I am the voice of God."

I saw the quote here: http://brighamyoungquotes.com/?s=blacks

This is an astounding batch of ammo if it is a true quote from BY. I'm looking for a source that would be acceptable to a TBM.

No I can't at the moment, but it certainly sounds like 'old brigham' to me. I suspect it might have been put together from different talks he gave or from the Journal of Discourses. I for one now will not rest until I solve this mystery.
Thanks for the topic.

I have a complete set in pdf searchable format and have found nothing.

I'm going through some pre-jornal sermons right now which are unfortunately unsearchable, but we'll find it.

Overall, this quote looks like a compilation of comments that he has made, judging by the uneven flow of words and the abscence of a source. But I'll try to keep looking- this disc has a ton of goodies on it.

looking over the website http://brighamyoungquotes.com/?s=blacks
that quote seems to be either a compilation of sayings or a creation to characterize BY; the quote itself is on the "About" page of the website with no documentation; but all other quotes on the web page have documentation.

It doesn't sound authentic - too many damning statements in one sentence. Sounds like something made up by a virulent "anti-Mormon".