In his book Mormon Portraits (pp.70-72), Dr. Wyl presents some revealing information:
Joseph Smith finally demanded the wives of all the twelve Apostles that were at home then in Nauvoo.... Vilate Kimball, the first wife of Heber C. Kimball, ... loved her husband, and he, ... loved her, hence a reluctance to comply with the Lord’s demand that Vilate should be consecrated....
They thought the command of the Lord must be obeyed in some way, and a “proxy” way suggested itself to their minds. They had a young daughter only getting out of girlhood; and the father apologizing to the prophet for his wife’s reluctance to comply with his desires, stating, however, that the act must be right or it would not be counselled ... asked Joe if his daughter wouldn’t do as well as his wife. Joe replied that she would do just as well, and the Lord would accept her instead. The half-ripe bud of womanhood was delivered over to the Prophet.
The fact that Joseph Smith asked for Heber C. Kimball’s wife but actually married his daughter is verified in the book The Life of Heber C. Kimball, written by Apostle Orson F. Whitney:
Before he would trust even Heber with the full secret, however, he put him to a test which few men would have been able to bear.
It was no less than a requirement for him to surrender his wife, his beloved Vilate, and give her to Joseph in marriage!
The astounding revelation well-nigh paraly[z]ed him. He could hardly believe he had heard aright. Yet Joseph was solemnly in earnest.... He knew Joseph too well ... to doubt his truth or the divine origin of the behest he had made....
Three days he fasted and wept and prayed. Then, with a broken and a bleeding heart, but with soul self-mastered for the sacrifice, he led his darling wife to the Prophet’s house and presented her to Joseph.
It was enough—the heavens accepted the sacrifice. The will for the deed was taken, and ‘accounted unto him for righteousness.’ Joseph wept at this proof of devotion, and embracing Heber told him that was all the Lord required....
The Prophet joined the hands of the heroic and devoted pair, and then and there, ... Heber and Vilate Kimball were made husband and wife for all eternity (Life of Heber C. Kimball, pp.333-35).
Poor, deceived fellow...