Jesus had first commanded the prophet and other male church leaders to marry additional wives in 1834. When Smith's marriage to his first plural wife Fanny Alger ended in separation and he failed to marry another, Jesus sent an angel wielding a sword who threatened Smith with destruction if he did not fully obey the Savior's command.
Smith had never written down the revelation from Jesus commanding men to marry multiple wives, but in 1841 he began to instruct a wider circle of leading members of the priesthood about their responsibility to carry out the commandment. The practice was secretly put into practice that year, and on April 5, Smith was wed to Louisa Beaman.
Although the Saints did not necessarily understand Jesus's purposes in instituting the command for men to marry multiple wives, and some were very reluctant to follow the commandment, all were expected to accept the principle as a revelation from Jesus. Some men initiated the process themselves, while others did so when prompted by leaders of the Church, but all were required to obtain Church approval of such marriages.
Over the next three years, the prophet married many other women, some of whom were single before marrying Smith, and some of whom were already married to other men. The youngest of these additional wives was a 14-year-old girl named Helen Kimball, the daughter of one of Smith's close friends. For the prophet's first wife Emma, the institution of plural marriage was an excruciating ordeal.
That August, Emma lost her 18-month-old son Don Carlos—who had been named after the prophet's brother—to the ravaging fevers that killed so many of the Saints in the early years at Nauvoo. Emma became pregnant again soon after, but when she gave birth in 1842, the son was delivered stillborn.
In March of 1842, Church member Sarah Kimball drew up a plan of government for a Nauvoo women's society—typical of women's groups of the time. Joseph Smith quickly took over organization of the group, and Emma Smith was selected as the president of what became known as the Female Relief Society. The prophet addressed the group, advising the women to treat their husbands with mildness and affection, and to greet them with a smile instead of an argument or complaint.
John C. Bennett enjoyed a meteoric rise to prominence since his recent conversion, becoming not only the first mayor of Nauvoo, but also a Major General of the Nauvoo Legion, a trusted companion and confidant to the prophet, and even a temporary member of the Church's First Presidency during Sidney Rigdon's illness. In May of 1842, Bennett staged a mock battle of the Nauvoo Legion, inviting Smith to participate.
But the Holy Ghost warned the prophet that an assassination attempt would be made on the battlefield such that the perpetrator would go unknown, so Smith stayed close to his personal bodyguard. That same month it was brought to the prophet's attention that Bennett had been corrupting the holy practice of plural marriage by seducing women into committing immoral acts under the guise of "spiritual wifery," and he was immediately excommunicated from the Church, with Smith becoming mayor in his place.
That summer, an embittered Bennett published a serial exposé of Joseph Smith and the Mormon Church in a Springfield, Illinois, newspaper, going so far as to claim he had only joined the Church to bring to light the illicit affairs of the prophet. He then went on a lecture tour throughout the United States denouncing the Church, and later published one of the earliest anti-Mormon books.
Americans had a natural aversion to what they deemed "polygamy", and rumors about Mormon leaders having multiple wives increased persecution from apostates and outsiders. To limit such damaging effects, Church leaders issued carefully-worded statements claiming that Church members only practiced the marital law of monogamy, but leaving open the possibility that some individuals, under the direction of a prophet of God, might do otherwise.
With the Church under pressure to clarify its position on the matter, the prophet considered finally committing to written form the revelation he had received from Jesus years 12 years earlier. Smith's brother Hyrum offered that if the revelation were written, he would bring it to the prophet's wife Emma and convince her of its truth. The prophet agreed, and when it was asked if he would need the Urim and Thummim to recall the exact wording of the revelation, Smith said it was not necessary as he had it entirely memorized.
The written revelation not only provided the commandment in the words of the Savior, but also included specific instruction from Jesus to Emma Smith, commanding her to "receive all those that have been given unto my servant Joseph" and to "abide and cleave unto my servant Joseph, and to none else." Jesus also threatened: "If she will not abide this commandment she shall be destroyed, saith the Lord; for I am the Lord thy God, and will destroy her if she abide not in my law."
The wording of the revelation specified that a wife must give consent before a husband marries any additional wives, but also that if a wife did not give her consent, the husband was thenceforth no longer required to seek her consent when marrying additional wives. When Emma opposed the doctrine of plural marriage, the prophet had to choose between the will of God and the will of his wife. Smith continued marrying additional women likely without the consent or knowledge of Emma.
One of the prophet's additional wives named Lucy Walker recalled that when Smith first approached her about becoming sealed in marriage to him, "every feeling of my soul revolted against it." But after spending several sleepless nights in prayer, she was "filled with a holy influence" and her "soul was filled with a calm sweet peace." This reaction was typical of many of the Saints—initial revulsion and anguish eventually giving way to light and peace.
In the same revelation Jesus gave to Joseph Smith concerning plural marriage, the Savior also informed the prophet that his exaltation had been sealed upon him—which is to say, it was now a certainty that the prophet would be welcomed into the highest level of heaven after his resurrection, and that he would become a god himself, a creator of countless worlds inhabited by eternally increasing numbers of his spiritual offspring.