During the last years of his life, the prophet Joseph Smith gave multiple public sermons dealing with 2 Peter 1, wherein the apostle Peter encourages his readers to “give diligence to make your calling and election sure” (vs. 10). Commenting on this phrase the prophet explained that to have one’s “calling and election” made sure meant to “obtain a promise from God for yourselves that you shall have eternal life.” And he explained that such a promise could be mediated through the keys restored by Elijah. By “this power of Elijah,” he said on one occasion, “we are sealed with the Holy Spirit of promise. [And] to obtain this sealing is to make our calling and election sure.” In another sermon he confirmed, “the power of Elijah is sufficient to make our calling and election sure.” 
In 2 Peter 1, Peter also speaks of obtaining the “more sure word of prophecy” (vs. 19), a phrase the prophet Joseph similarly interpreted to mean “a man’s knowing that he was sealed up unto eternal life … through the power of the Holy priesthood.”  
This was the theology—the possibility of being sealed up unto eternal life under the keys restored by Elijah. 
Then came the practice. 
Beginning in 1843 in Nauvoo, the prophet introduced a sacred ordinance to his most trusted associates wherein, using the keys of Elijah which he held, husbands and wives were sealed up unto eternal life. This was not the marriage ordinance. This was more, given to those already married. It was an ordinance sometimes referred to in the historical record as “the second anointing.” 
In this episode of Church History Matters, Casey and Scott discuss what they know about the theology and early practice of the second anointing. We also discuss the early—and now discontinued—sealing practice called “the law of adoption” wherein men and women were sealed into the families of Church leaders as their children. They also briefly touch on the now extinct practice of temple-like prayer circles that were conducted outside of the temple for many years in our history. 
For show notes and transcript for this and other episodes go to https://doctrineandcovenantscentral.org/church-history-matters-podcast/