Continuing on from the theme of my previous post, a natural question is what led Joseph Smith to the idea of plural marriage in the first place?
This question is kind of hard to answer because Joseph did not, to my knowledge, record any personal reflections on the topic. He was singularly reticent on this difficult topic. So we are left to speculate.
What we know is that Joseph Smith finished translating the Book of Mormon in 1829, and the book was published in 1830. Most likely, the last thing that Joseph translated was the Small Plates of Lehi, which is now the first part of the Book of Mormon. See Richard L. Bushman, Joseph Smith: Rough Stone Rolling at 74 (Vintage Books 2007). (Bushman’s biography is excellent, and I recommend it to anybody who wants a fair but not whitewashed account of Joseph Smith’s life.)
So when Joseph took up his translation of the Bible in 1830, the stern prohibition against polygamy in Jacob 2 was probably fresh in his mind. Most likely, Joseph had given little thought to Jacob’s qualifying aside, “For if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people; otherwise they shall hearken unto these things.” Indeed, it’s possible he didn’t even understand yet that this meant that the Lord sometimes commanded His people to practice plural marriage.
How puzzling it must have been, then, when Joseph began translating the Book of Genesis, and was reminded that great patriarchs like Abraham and Jacob had practiced plural marriage. Or that the great prophet Moses, whose tremendous vision was the subject of the Book of Moses, also had multiple wives. This may have seemed inconsistent with what Jacob taught.
So as was typical for him, Joseph asked the Lord. It may have been as early as 1830 or 1831 when the Lord first instructed him in the principles of the sometimes-authorized practice of plural marriage. It was apparently not long after that when Joseph first learned that this was not an abstract or hypothetical doctrine that belonged only to antiquity. He would be commanded to restore this doctrine along with the rest of the gospel; he would not only have to reveal it, but he would also be required to practice it.
Joseph was understandably reluctant. He loved Emma dearly, and he was not inclined to either break her heart or suffer her wrath (she was, by all accounts, a rather fiery woman). Joseph later recounted that an angel came to him three times between the years 1834 and 1842, warning Joseph that he would obey this principle, or he would be destroyed. On at least one occasion, the angel had a drawn sword in hand. Bushman at 437 — 8. Joseph did not publish D&C Section 132 until 1843, barely a year before he was murdered by a mob that was agitated largely over this very principle.
In summary, plural marriage was not a principle that Joseph conceived of whole cloth one day and immediately began practicing. Like much of the restoration, it appears to have come in bits and pieces over time. If there is anything singular about it, it is in Joseph’s resistance to the will of the Lord on this one point, where in most other respects, he was quick to obey. No doubt Joseph foresaw apparent impropriety, loss of friends, saints falling away, and persecutions from those who found the doctrine reprehensible to their Christian sensibilities. Unfortunately, he was right on every point.