The Church of Jesus Christ of Latter-day Saints teaches that baptism is essential to salvation. Since many people have died without being baptized, or because they were baptized outside the LDS Church, they cannot obtain exaltation, or godhood.
However, “Because God is merciful, He has prepared a way for all people to receive the blessings of baptism,” according to the church’s official website. “By performing proxy baptisms in behalf of those who have died, Church members offer these blessings to deceased ancestors. Individuals can then choose to accept or reject what has been done in their behalf.”
The LDS Church cites Jesus as its primary source for the necessity of baptism (John 3:5), and posits that “baptisms for the dead were done during the Apostle Paul’s time (1 Cor. 15:29). This practice has been restored with the establishment of the Church of Jesus Christ of Latter-day Saints. The Prophet Joseph Smith first taught about the ordinance of baptism for the dead during a funeral sermon in August 1840.”
No doubt, Paul’s statement about baptism for the dead has been widely misunderstood – and much abused. In his teaching on the resurrection, Paul inserts the statement, “Otherwise, what do people mean by being baptized on behalf of the dead? If the dead are not raised at all, why are people being baptized on their behalf?” (1 Cor. 15:29 ESV).