[Helen Mar Kimball]
The Prophet said that the practice of this principle would be the hardest trial the Saints would ever have to test their faith. It was not his work, but that of the Almighty, and he said it would cause the damnation of all who entered into it with impure motives, and none who acted unrighteously could stand, the trial would be so great; and there would be but few men who would be capable of being saviors upon Mount Zion.
He taught the principle to his wife, Emma, who humbly received it and gave to him three young women to wife, who had been living with her in her family, and had been like adopted daughters. Until she lost the spirit and her heart became hardened, they lived happily together. They respected and loved her as though she had been their mother, and might have remainded with her afterwards had they been willing to have severed the ties between themselves and the Prophet; but choosing to remain true to their covenants, which they considered binding here and hereafter, they preferred to leave the Mansion.
Emma deceived her children and denied to everyone that the Prophet had ever received a revelation on celestial marriage, or had ever practiced it, although she had heard the revelation and was an eye witness to the marriage of the three wives above mentioned. Besides, he told her of every one that had been sealed to him.
Some of those who apostatized from the Church, and knew more than she did about the practice of polygamy, also denied it; but there are too many of the Prophet's wives still living in Utah—as well as hundreds of other witnesses—who can testify to the hypocrisy of those men who, like William Marks, apostatized because they could not manage matters pertaining to the Church as they desired, and who afterwards volunteered their services to help Emma Smith, she having, according to her own acknowledgment, founded the Josephite church to revenge herself upon Brigham Young.
... My father was often called a prophet, and years ago in Nauvoo I heard him predict that it would yet become a law of this nation that men should marry a plurality of wives.
[Whitney, Helen Mar, Jeni Broberg Holzapfel, and Richard Neitzel Holzapfel, A Woman's View: Helen Mar Whitney's Reminiscences of Early Church History, Provo, UT: Religious Studies Center, Brigham Young University, 1997]