I could not find the first quote or anything like it in the GospeLink database, which has a lot of literature authored by Mormon leaders over the years. Its absence there and anywhere on the internet–where quotes to that effect are premium for setting up debunking arguments–is significant. Are there any more clues in your manuscript, like its author or date?

The Journal of Discourses quote is fairly easy to locate on the net. No doubt it is probably the most embarrasing quote made by a Prophet in LDS church history.

>>I don’t know whether that is what Mormonism has held, either early on or more recently.

What is currently considered doctrine is easier to point out than what was considered doctrine back then. The best source to quote on this, if you are doing a scholarly paper, is Dr. Millet.

“What is our doctrine? What do we teach today?” I indicated that if some teaching or idea was not in the standard works, not among official declarations or proclamations, was not taught currently by living apostles or prophets in general conference or other official gatherings, or was not in the general handbooks or official curriculum of the Church, it is probably not a part of the doctrine or
teachings of the Church.

http://tinyurl.com/ja78q

This is found in an article on the LDS church website. If you need more authorative, primary, references let me know. Following Dr. Millet, the quote is definitely NOT considered doctrine today.

I wrote an article for FAIR — an LDS apologetics organization I am a part of, but don’t speak for — that may serve as an introduction to race relations in the past:
http://www.fairwiki.org/wiki/index.php/Blacks_and_the_priesthood
Also check out:
http://www.fairwiki.org/wiki/index.php/Fallibility_of_prophets

If we ask if the quote was doctrine when it first came out, I would have to answer with a qualified yes, as it was taught by an authority at an official gathering (I assume). However, Mormons do not hold their Prophets to be infallible like the Pope. This item wouldn’t be considered “binding” because a belief is only binding if it is accepted by common consent by all the members.

I have yet to see an interpretation of the quote I am comfortable with. If you are interested, I will take a stab at what I think Brigham was really saying. Feel free to skim or read my references, get a feel for landscape, and ask any follow up questions.

Brigham Young, speaking as “a Prophet from God who cannot teach false doctrine and cannot be misled concerning a law of God,” proclaimed, among other things: “Shall I tell you the Law of God with 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.” (Journal of Discourses, Vol. X, p. 110)

The top part, about a Prophet not being able to teach false doctrine, has no source listed, and I don’t know whether that is what Mormonism has held, either early on or more recently. Could you tell me, or give me a source on the importance of the teaching of the Mormon Prophets? (I mean, of how binding their words are for Mormons?) And, how important, doctrinally, are the Journal of Discourses?
I know very little about Mormonism, and don’t want to write anything without immediate reference to primary sources.

Any help would be greatly appreciated.

Peace,
Joseph Woodard