The fourth Article of Faith of The Church of Jesus Christ of Latter-day Saints states that baptism by immersion for the remission of sins, and the laying on of hands (or confirmation) for the gift of the Holy Ghost are the first two ordinances of the gospel of Jesus Christ. If a person is going through the temple for him- or herself, he or she will have already been baptized and confirmed a member of the church. Why do baptisms take place in the temple, then, and why for the dead? Paul taught this concept, “Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?” (1 Corinthians 15:29). The concept is a simple one. Not everyone who has lived or who will live on this earth has had the opportunity to hear about Jesus Christ. Should they be sent to an endless torment in hell because they never had the opportunity to be baptized? Of course not.
Mormon doctrine teaches that all members of the Mormon Church should do all they can to research their family history and to bring their family names to the temple. Family history work is a key part of Mormon doctrine, because Mormons believe that families can be together forever. This is not an automatic guarantee, though. There is a lot of work that needs to be done.
When a person goes through a Mormon temple for the first time, he or she is performing ordinances there for him- or herself. Every time a person goes back to do an ordinance, it is being done for someone else by proxy. This means that a person is standing in for someone who died without the chance to receive these ordinances personally. Billions upon billions of people have lived upon this earth with no knowledge of our Savior, Jesus Christ. By doing work by proxy for them, the law of mercy is being extended to them. A just God would not sentence them to hell for something that was no fault of theirs.
Nearly all names which have been submitted to the temple to have these ordinances done by proxy were submitted by family members. If a person brings personal names to the temple to do the work for others who have passed on, they must be personal family names. Occasionally exceptions are made to this rule; for example, if a good friend passes away and there are no other Mormons in their family. If permission is obtained from the nearest living relative of the deceased, that name may be taken to the temple. In all other cases, names for whom work is done have been submitted by family members.
Work done in Mormon temples is a completely selfless form of service. People sacrifice their time to complete these ordinances on behalf of other people. Mormon doctrine teaches that free will is an eternal principle. So, just because temple work is done for a person, that does not take that person’s choice away about whether they want to accept those ordinances. If a person for whom this work is done does not believe in its truth, or if he or she simply does not want to take upon him- or herself the commitments these ordinances include, that is fine. No one is forced to accept this work. However, by making sure it is done, then people on the other side at least have a choice, whereas before, they had none.
The Church of Jesus Christ of Latter-day Saints has an incredible family history program, which is open to all people, whether they are members of the Mormon Church or not, free of charge. The Mormon Church has gained access to countless countries’ records, has digitized countless records, and these are all available for free.
LDS News on Church policy regarding baptism for the dead