Here's a really good source on this.
http://www.connellodonovan.com/black_white_marriage.htmlAppleby wrote a letter to Brigham Young, informing him of this situation and wanting to know if the church indeed approved of blacks holding priesthood and marrying white women:
At Lowell…I found a coloured brother by name of ‘Lewis’ a barber, an Elder in the Church, ordained some years ago by William Smith. This Lewis I was informed has also a son who is married to a white girl and both members of the Church there. Now dear Br. I wish to know if this is the order of God or tolerated in this Church ie to ordain Negroes to the Priesthood and allow amalgamation [inter-racial marriage]. If it is I desire to Know, as I have Yet got to learn it.[9]
Almost a month later, Appleby decided to investigate further and went to the Enoch Lewis home to witness their relationship:
In looking for a Br. in the Church, I called at a House, a coloured man resided there, I set myself down for a few moments presently in came quite a good looking White Woman, about 22 years old I should think, with blushing cheeks, and was introduced to me as the negro’s wife, an infant in a cradle near bore evidence of the fact. Oh! Woman, thought I, where is thy shame, (for indeed I felt ashamed and not only ashamed, but disgusted, when I was informed they were both members of a Church!) [Where is] Respect for thy family, thyself, for thy offspring and above all the law of God?[10]
While Brigham Young’s adulterous relationship was going public in Massachusetts and throughout the nation, we turn to Young at Winter Quarters and what happened there. Brigham Young was already long aware of black Mormons Walker Lewis and Joseph T. Ball holding priesthood, having known Lewis and Ball for many years when Young was serving missions in the Boston and Lowell area. Here in Nauvoo, Brigham Young told recently ordained Warner McCary that holding the priesthood had nothing to do with race.[14] On March 26, 1847, Young told McCary that holding LDS priesthood had “nothing to do with the blood for [from] one blood has God made all flesh, we have to repent [to] regain what we av lost" (a paraphrase of Acts 17:26). I emphasize that in March 1847, Young said that there was no priesthood ban because of race using Acts as a proof text– we are all ONE BLOOD; the only stipulation is repentance. But by December 1847, this is all changed.
As I noted earlier Pres. Appleby wrote a report to Brigham Young about his discovery of Enoch Lewis’s marriage to Matilda Webster. He mailed this report to Brigham Young with an address at Council Bluff, Iowa, where it was then forwarded to Winter Quarters, Nebraska, and there remained. Young, of course, was just settling in Utah at the time, so the acting Mormon president did not receive the letter for some six months. Ironically, Appleby’s letter, Brigham Young, and William I. Appleby himself, all converged at Winter Quarters at the beginning of December 1847. Brigham Young returned to Winter Quarters from the Salt Lake Valley, when Elder William I. Appleby arrived there on December 2 from his mission presiding over the eastern states. Young read Appleby’s letter regarding the marriage of Enoch and Matilda Lewis and then immediately met with Appleby in person to ensure the accuracy of the details of the inter-racial marriage of Enoch and Mary Matilda Lewis.
As shown, by December 1847, things had significantly changed for Brigham Young. Warner McCary had come out in open rebellion against the church and had started his own version of Mormonism, including a highly sexualized sealing ceremony, in which McCary was “sealed” to the white women of his disciples by sleeping with them. In response to all this, Young called a meeting of the members of the Twelve who were present in Winter Quarters, and had Appleby appear to personally give an account. Here are Thomas Bullock’s minutes of that meeting:
1847 Minutes of the Twelve
December 3, 1847 Minutes of the Quorum of the Twelve, pp. 6-7
(Click on Image to Enlarge)
bro Appleby relates...
Wm. Smith ordained a black man Elder at Lowell[15] & he has married a white girl & they have a child
Prest. Young If they were far away from the Gentiles they wod. [would] all on [sic - ot? ought?] to be killed - when they mingle seed it is death to all.
If a black man & white woman come to you & demand baptism can you deny them? the law is their seed shall not be amalgamated
Mulattoes r like mules they cant have children, but if they will be Eunuchs for the Kingdom of God Heaven's sake they may have a place in the Temple[16]
B. Y. The Lamanites r purely of the house of Israel & it is a curse that is to be removed when the fulness of the Gospel comes –
O. H. Has taught that if girls marry the half breeds they r throwing themselves away & becoming as one of them
B. Y. It is wrong for them to do so.
B. Y. The Pottawatamies will not own a man who has the negro blood in him – that is the reason why the Indians disown the negro prophet [Warner McCary]. [17]
It is here in this meeting that the Mormon theology prohibiting marriages between blacks and whites was born. Although the minutes are extremely sparse, they are densely compacted with theological themes that will be carried on into the following decades.
Black-White Marriage in Mormon Theology
With this meeting of Young and the other apostles, we have the first LDS attempts at formulating a theology that prohibited black-white marriage. Below are the seven main theological points I have found in authoritative LDS statements throughout the decades (although some slightly overlap with each other). Most of these points originated at the December 1847 meeting of Young and the Apostles with Pres. Appleby. Again I point out how similar most of these points are to current LDS theological arguments against homogamy, or same-sex marriage.
It is prohibited and contrary to church doctrine from ancient times – “The law is their seed shall not be amalgamated”
It would lead to the annihilation of the human species, since mixed-race children cannot reproduce - “Mulattoes are like mules”
It and the reproduction of mixed-race children requires blood atonement for those who are Latter-day Saints – “this will always be so”
It is a “great sin”
The interracial marriage of Ham & Egyptus brought “tainted” black blood – and its priesthood/temple curse – through the universal flood
Racial segregation is a necessary evil to prevent black-white marriage en masse and total genetic chaos of white and black races, leading to the complete loss of the priesthood on earth, the destruction of the LDS Church, and the loss of exaltation in the Celestial Kingdom for all humanity - “When they mingle seed, it is death to all”
It is a “virus” and will spread contagiously