Law of adoption
"[E]arly Mormons sealed living men to other men in an unusual ceremony known as the law of adoption. Thus a man could have any number of men adopted to himself as his sons for eternity." 
"Not many Mormons know that in the early days of the church, the Law of Adoption was practiced to seal living men to other men. Through this ordinance, a man could have any number of men sealed to himself as his sons for eternity. According to Gordon Irving, who worked for the Historical Department of the church:" 
- "No consensus exists with regard to the date when the first adoptions were performed…It is certainly possible, perhaps probable, that Joseph Smith did initiate certain trusted leaders into the adoptionary order as early as 1842." (Brigham Young University Studies, Spring 1974, p. 295)
- "The father may be either younger or older than the son, but in any case assumes the character of guardian, with full control of the labor and estate of the adopted son. Many young men give themselves over to the leaders as 'eternal sons,' in the hope of sharing the honor of their adopted parents." (History of Utah, p. 361)
- "Many other interesting & important items were presented by President Young much to our edifycation. Meeting was dismissed & met again at 2 oclok & was addressed in a vary edifying manner by O Pratt & treated upon the same principles spoken off by Br Young. Among his remarks He said that as all the ordinances of the gospel Administered by the world since the Aposticy of the Church was illegal, in like manner was the marriage Cerimony illegal and all the world who had been begotten through the illegal marriage were Bastards not sons & Hence they had to enter into the law of adoption & be adopted into the Priesthood in order to become sons & legal heirs of salvation." (Wilford Woodruff's Journal, Vol. 3, August 15, 1847, p. 260)
- "Difficulties began when it became apparent that adoption gave one a special status and that not all the adopted enjoyed the same status…
"Adoption as a system of social organization was troubled not only by fathers who demanded too much of their sons, but also by some of the children who in turn expected too much from their fathers…In theory the importance of adoption lay in the validation of one's sonship in the family of God. But some were more interested in being fathers and exercising authority over others than they were in being sons of God. Kingdom-building, or the gathering together of a large number of people over whom one could rule in eternity, enjoyed a good deal of popularity. Brigham Young complained: were I to say to the elders you now have the liberty to build up your kingdoms, one half of them would lie, swear, steal and fight like the devil to get men and women sealed to them. They would even try to pass right by me and go to Jos[eph]…"(Brigham Young University Studies, Spring 1974, pp. 299-303)
- “By this power, men will be sealed to men back to Adam, completing and making perfect the chain of the Priesthood from this day to the winding-up scene. I have known men that I positively think would fellowship the Devil, if he would agree to be sealed to them. ‘Oh, be sealed to me, brother; I care not what you do. You may lie and steal, or anything else, I can put up with all your meanness, if you will only be sealed to me.’ Now this is not so much weakness as it is selfishness. It is a great and glorious doctrine, but the reason I have not preached it in the midst of this people, is I could not do it without turnaing so many of them to the Devil. Some would go to hell for the sake of getting the Devil sealed to them.” (Journal of Discourses, Vol. 9, p. 269).
- Sealing Men to Men: An Early Mormon Doctrine, by Jerald & Sandra Tanner
- Temple adoptions were part of LDS evolution toward genealogy work, by Doug Gibson
- The Lord Will Redeem His People: Adoptive Covenant and Redemption in the Old Testament and Book of Mormon, by Jennifer Clark Lane
- The Law of Adoption: One Phase of the Development of the Mormon Concept of Salvation, 1830–1900, by Gordon Irving - "As established in 1830, The Church of Jesus Christ of Latter-day Saints was hardly a finished product. Although the new faith possessed distinctive characteristics, many significant aspects of Mormon thought and practice were revealed and developed in the years that followed. Among these was the law of adoption, which lay at the heart of the Mormon conception of salvation, and which grew out of theological principles taught by the founding prophet, Joseph Smith. These principles were given a special interpretation by Brigham Young and his generation and were finally refined by a revelation announced by Wilford Woodruff in the 1890s which broadened and universalized the concept of salvation which had been preached in the Church for fifty years."
- The Evening and the Morning Star #2: The Law of Adoption