Why do Mormons baptize the dead?
Virtually every religion in the world has certain unique doctrines, which are important to insiders and sometimes misunderstood by outsiders, and the religion founded by Joseph Smith is no different. Many people would say that the Latter-Day Saints practice of baptizing the dead fits that description. The practice is, nevertheless, sacred to church members. It reflects Mormon beliefs, which teach that people have a second chance at salvation after physical death.
Baptism for the dead is carried out by proxy; meaning, it's done vicariously (i.e. by using a substitute person). In other words, LDS church members aren't using corpses of the dead to accomplish this ordinance. Rather, a living person is baptized as the deceased person's representative. Baptizing the dead is also practiced by other Mormon sects as well as by other religions in the world like the Mandaeans of Iraq and Iran, some of the Neo-Apostolic congregations of Europe, and some Native American religions.
By proxy baptism in the LDS church
The temple ritual
In the Mormon rite of baptism for the dead, a living person acting as a proxy is baptized by immersion in typical Latter-day Saint fashion. The ordinance is performed only in temples. The prayer accompanying the baptism differs from typical wording in that it states that the baptism is being performed for, and in behalf of, a deceased person whose name has been submitted for that ordinance. Any member of the Church who is at least 12 years old may be baptized for the dead. Young men must hold the priesthood.
The Latter-day Saints' view of baptism of the dead is based on their view of baptism in general. Mormons believe firmly that personal baptism is a required ordinance for those who desire to enter the kingdom of God.
Baptism for the dead allows this saving ordinance to be offered to all those who have died without having heard of the Gospel of Jesus Christ. If baptism is a required ordinance, as Mormons believe is evidenced by Jesus's own desire to receive it from John the Baptist, then this ordinance becomes a burden for all those who wish to spread the Gospel with all the inhabitants of the earth who have previously passed on to the afterlife.
According to the Church of Jesus Christ of Latter-day Saints, their practice of baptism for the dead is based on a revelation Joseph Smith received. Smith first taught the doctrine at the funeral sermon of a deceased member of the Church, Seymour Brunson.Source"
- "Baptism for the dead." Wikipedia, accessed October 2005. Text used under GFDL.
- Baptism for the Dead - article from Encyclopedia of Mormonism on unofficial LDS website
- Questions about baptism for the dead - LDS FAQ at JeffLindsay.com (unofficial LDS website)