for what it's worth, I was curious about the circumstanced regarding Hyrum's "conversion" to polygamy. Here is how Van Wagoner describes it:
Emma was not the only Smith strongly opposed to polygamy. Joseph received almost as much opposition from his brother Hyrum as from Emma. After citing an anti-polygamy passage from the Book of Mormon (2 Jac.) in his 14 May 1843 public denouncement of the practice, Hyrum "Said there were many that had a great deal to say about the ancient order of things Solomon & David having many wifes & Concubines—but its an abomination in the Sight of God.… If an angel from heaven should come and preach such doctrine, [you] would be sure to see his cloven foot and cloud of blackness over his head" (Levi Richards Journal, 14 May 1843).
[p.55] The following day Hyrum joined William Law, William Marks, and perhaps others in a conspiracy to ferret out evidence of Smith's polygamous relationships. William Clayton recorded in his 23 May diary a conversation with Heber C. Kimball "concerning a plot that is being laid to entrap the brethren [involved in polygamy] … by bro H[yrum], and others." Hyrum related to Marks that "he did not believe in it [polygamy] and he was going to see Joseph about it, and if Joseph had a revelation on the subject, he would believe it" (Newell and Avery 1984, 141).
Before he had a chance to talk with Joseph, however, Hyrum ran into Brigham Young. Young reported in an 1866 address that the two sat down together on fence rails piled on the Masonic Hall lot. According to Young, Hyrum said he knew that "you and the twelve know some things that I do not know. I can understand this by the motions, and talk, and doings of Joseph, and I know there is something or other, which I do not understand, that is revealed to the Twelve. Is this so?" The canny Young, aware of Hyrum's entrapment plans, replied: "I do not know any thing about what you know, but I know what I know."
But Hyrum would not be denied: "I have mistrusted for a long time that Joseph has received a revelation that a man should have more than one wife, and he has hinted as much to me, but I would not bear it.… I am convinced that there is something that has not been told me." Young requested Hyrum to "sware with an uplifted hand, before God, that you will never say another word against Joseph and his doings, and the doctrines he is preaching to the people." After Hyrum consented, Young revealed: "Joseph had many wives sealed to him. I told him the whole story, and he bowed to it and wept like a child, and said 'God be praised.' He went to Joseph and told him what he had learned, and renewed his covenant with Joseph" (Young, Unpublished Address).
Evidently it was at this time that Smith explained to Hyrum the full meaning of "celestial marriage." Hyrum's first wife, Jerusha Barden, had died on 13 October 1837. Smith explained: "You can have her sealed to you upon the same principle as you can be baptized for the dead." "What can I do for my second wife?" Hyrum asked. "You can also make a covenant with her for eternity and have her sealed to you by the authority of the Priesthood," the prophet advised. Hyrum discussed the ordinance with his living wife, Mary Fielding Smith, and she responded, "I will act as proxy for your wife that is dead and I will be sealed to you for eternity myself for I never had any other husband. I love you and I do not want to be separated from you nor be forever alone in the world to come" (Ms History, 8 April 1844).
Less than two months later Hyrum became the catalyst for Smith's receiving the key revelation on "celestial marriage" (D&C 132). On 12 July the brothers, along with William Clayton, were in Smith's office discussing [p.56] Emma's opposition to polygamy. Hyrum still harbored concerns that polygamy was adulterous. Charles Smith, a Nauvoo elder, later said that Hyrum told the Elders' Quorum in the winter of 1843-44 "that the doctrine of Plurality of Wives had bothered him considerably and he felt constrained to ask wherein Abraham, Moses, David & others could be justified before God in practicing this to him repugnant doctrine—He asked his brother the Prophet Joseph to ask the question of the Lord—Joseph did so and the Revelation given 12 July 1843 was the answer" (St. George Record).
Richard S. Van Wagoner, Mormon Polygamy, p.55
