May 1843 - Joseph Smith (Age: 37) married Lucy Walker (Age: 17).
"The Walker family arrived in Nauvoo in the spring of 1841. That summer Lucy’s Mother contracted malaria and died months later in January 1842, leaving ten children. Her Father, John, was heartbroken and his health, “seemed to give way”. Lucy remembers, “The Prophet came to the rescue. He Said, if you remain here Bro. Walker, you will soon follow your wife. You must have a change of scene, a change of climate. You have Just such a family as I could love. My house shall be their home...place the little ones with kind friends, and the four Eldest shall come to my house and [be] received and treated as my own children...” The change of scene and climate that Joseph had in mind for John Walker was a two year mission to the eastern states. In response to this arrangement Lucy said, “I rung my hands in the agony of despair at the thought of being broken up as a family, and being sepparated from the little ones...” Never-the-less, fifteen-year-old Lucy moved into the Prophets house." (Mormon Enigma: Emma Hale Smith pg 89; In Sacred Loneliness: The Plural Wives of Joseph Smith pg 461,462)
"While living in the Smith home, Lucy remembers: “In the year 1842 President Joseph Smith sought an interview with me, and said, ‘I have a message for you, I have been commanded of God to take another wife, and you are the woman.’ My astonishment knew no bounds. This announcement was indeed a thunderbolt to me...He asked me if I believed him to be a Prophet of God. ‘Most assuredly I do I replied.’...He fully Explained to me the principle of plural or celestial marriage. Said this principle was again to be restored for the benefit of the human family. That it would prove an everlasting blessing to my father’s house.”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 463)
"“What do you have to Say?” Joseph asked. “Nothing” Lucy replied, “How could I speak, or what would I say?” Joseph encouraged her to pray: “tempted and tortured beyond endureance until life was not desirable. Oh that the grave would kindly receive me that I might find rest on the bosom of my dear mother...Why – Why Should I be chosen from among thy daughters, Father I am only a child in years and experience. No mother to council; no father near to tell me what to do, in this trying hour. Oh let this bitter cup pass. And thus I prayed in the agony of my soul.”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 464)
"Joseph told Lucy that the marriage would have to be secret, but that he would acknowledge her as his wife, “beyond the Rocky Mountains”. He then gave Lucy an ultimatum, “It is a command of God to you. I will give you untill to-morrow to decide this matter. If you reject this message the gate will be closed forever against you.” Lucy said, “This arroused every drop of scotch in my veins...I felt at this moment that I was called to place myself upon the altar a liveing Sacrafice, perhaps to brook the world in disgrace and incur the displeasure and contempt of my youthful companions; all my dreams of happiness blown to the four winds, this was too much, the thought was unbearable.”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 464)
"Now, bearing the burden of her own eternal salvation and that of her family, and with a deadline approaching, Lucy prayed more fervently for an answer. She couldn’t sleep the entire night. Just before dawn, and Joseph’s deadline, she “received a powerful and irristable testimony of the truth of the mariage covenant called 'Celestial or plural mariage'” and "I afterwards married Joseph as a plural wife and lived and cohabitated with him as such." Lucy married Joseph on May 1, 1843. At the time, Emma was in St. Louis buying supplies for the Nauvoo hotel. Lucy remembers, “Emma Smith was not present and she did not consent to the marriage; she did not know anything about it at all.” Of the relationship, Lucy said, “It was not a love matter, so to speak, in our affairs, -at least on my part it was not, but simply the giving up of myself as a sacrifice to establish that grand and glorious principle that God had revealed to the world.”" (Mormon Enigma: Emma Hale Smith pg 139; Mormon Polygamy: A History pg 59; In Sacred Loneliness: The Plural Wives of Joseph Smith pg 465)
"After Joseph was killed in June 1844, Lucy married Heber C. Kimball. Explaining the relationship, Lucy said, “...The contract when I married Mr. Kimball was that I should be his wife for time, and time only, ...and in the resurrection [he] would surrender me, with my children, to Joseph Smith.”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pgs 466,467)
"Brigham Young taught that “no man or woman in this dispensation will ever enter into the celestial kingdom of God without the consent of Joseph Smith.” As Heber lay on his death bed he called Lucy to his side and hoping to win favor with Joseph Smith, asked her, “What can you tell Joseph when you meet him? Cannot you say that I have been kind to you as it was possible to be under the circumstances? I know you can, and am confident you will be as a mediator between me and Joseph...”" (Journal of Discourses vol 7 pg 289; In Sacred Loneliness: The Plural Wives of Joseph Smith pg 457)
Source Material: http://wivesofjosephsmith.org/23-LucyWalker.htm