Many early converts to the religion including Brigham Young, Orson Pratt, and Lyman Johnson, recorded that Joseph Smith was teaching plural marriage privately as early as 1831 or 1832. Pratt reported that Smith told some early members in 1831 and 1832 that plural marriage was a true principle, but that the time to practice it had not yet come. Johnson also claimed to have heard the doctrine from Smith in 1831. Mosiah Hancock reported that his father was taught about plural marriage in the spring of 1832.
The 1835 and 1844 versions of the church's Doctrine and Covenants (D&C) prohibited polygamy and declared that monogamy was the only acceptable form of marriage:
In as much as this church of Christ has been reproached with the crime of fornication, and polygamy: we declare that we believe, that one man should have one wife; and one woman, but one husband, except in the case of death, when either is at liberty to marry again.
William Clayton, Smith's scribe, recorded early polygamous marriages in 1843, including unions between Smith and Eliza Partridge, Emily Partridge, Sarah Ann Whitney, Helen Kimball and Flora Woodworth. Clayton relates: "On the 1st day of May, 1843, I officiated in the office of an Elder by marrying Lucy Walker to the Prophet Joseph Smith, at his own residence. During this period the Prophet Joseph took several other wives. Amongst the number I well remember Eliza Partridge, Emily Partridge, Sarah Ann Whitney, Helen Kimball and Flora Woodworth. These all, he acknowledged to me, were his lawful, wedded wives, according to the celestial order. His wife Emma was cognizant of the fact of some, if not all, of these being his wives, and she generally treated them very kindly."
As early as 1832, Mormon missionaries worked successfully to convert followers in Maine of polygamist religious leader Jacob Cochran, who went into hiding in 1830 to escape imprisonment due to his practice of polygamy. Among Cochran's marital innovations was "spiritual wifery", and "tradition assumes that he received frequent consignments of spiritual consorts, and that such were invariably the most robust and attractive women in the community". The majority of what became the Quorum of the Twelve in 1835 attended Mormon conferences held in the center of the Cochranites in 1834 and 1835. Brigham Young, an apostle of the church, became acquainted with Cochran's followers as he made several missionary journeys through the Cochranite territory from Boston to Saco, and later married Augusta Adams Cobb, a former Cochranite.
Joseph Smith publicly condemned polygamy, denied his involvement in it, and participants were excommunicated, as church records and publications reflect. But church leaders nevertheless began practicing polygamy in the 1840s, particularly members of the Quorum of the Twelve. Sidney Rigdon, while he was estranged from the church, wrote a letter in backlash to the Messenger and Advocate in 1844 condemning the church's Quorum of the Twelve and their alleged connection to polygamy:
It is a fact so well known that the Twelve and their adherents have endeavored to carry on this spiritual wife business … and have gone to the most shameful and desperate lengths to keep from the public. First, insulting innocent females, and when they resented the insult, these monsters in human shape would assail their characters by lying, and perjuries, with a multitude of desperate men to help them effect the ruin of those whom they insulted, and all this to enable them to keep these corrupt practices from the world.
At the time, the practice was kept secret from non-members and most church members. Throughout his life, Smith publicly denied having multiple wives.
However, John C. Bennett, a recent convert to the church and the first mayor of Nauvoo, used ideas of eternal and plural marriage to justify acts of seduction, adultery and, in some cases, the practice of abortion in the guise of "spiritual wifery". Bennett was called to account by Joseph and Hyrum Smith, and was excommunicated from the church. In April 1844, Joseph Smith referred to polygamy as "John C. Bennett's spiritual wife system" and warned "if any man writes to you, or preaches to you, doctrines contrary to the Bible, the Book of Mormon, or the book of Doctrine and Covenants, set him down as an imposter." Smith mused
we cannot but express our surprise that any elder or priest who has been in Nauvoo, and has had an opportunity of hearing the principles of truth advanced, should for one moment give credence to the idea that any thing like iniquity is practised, much less taught or sanctioned, by the authorities of the Church of Jesus Christ of Latter Day Saints.
The practice was publicly announced in Salt Lake City, Utah Territory, in 1852, some five years after the Mormons arrived in Utah, and eight years after Smith's death. The doctrine authorizing plural marriage was published in the 1876 version of the LDS Church's Doctrine and Covenants.
Teachings on the multiple wives of God and Jesus
Top leaders used the examples of the polygamy of God the Father and Jesus Christ in defense of it and these teachings on God and Jesus' polygamy were widely accepted among Mormons by the late-1850s. In 1853 Jedediah Grant who later become a First Presidency member stated that the top reason behind the persecution of Christ and his disciples was their due to their practice of polygamy. Two months later the apostle Orson Pratt taught in an official church periodical that "We have now clearly shown that God the Father had a plurality of wives," and that after her death, Mary (the mother of Jesus) may have become another eternal polygamous wife of God. He also stated that Christ had multiple wives as further evidence in defense of polygamy. In the next two years the apostle Orson Hyde also stated during two general conference addresses that Jesus practiced polygamy and repeated this in an 1857 address. This teaching was alluded to by church president Brigham Young in 1870 and then First Presidency member Joseph F. Smith in 1883.