I spent part of this evening watching the parade of athletes in the Olympic opening ceremonies. The mix of nations, peoples, languages, costumes, and religions in this parade is always thought-provoking. As a Christian, how do you reconcile the fact that billions of people on the earth, from many of these nations, will not fully learn about the teachings of Christ during their lives, even though His is the only name under which salvation can come? Will they be condemned for this in the afterlife?
An excellent commentary from LDS Newsroom, titled Everyone Else Makes Such Lonely Heavens, describes the Mormon belief that a just God could not condemn his children for something they have no control over in this life. The article gives a brief but accurate overview of the Mormon belief in performing baptisms on behalf of people who have died, so that they can have the opportunity to accept Jesus after this life. The doctrine of baptism for the dead upholds the Christian belief that salvation must come through Christ, without unjustly condemning those who did not have the opportunity to hear about or accept Christ's teachings in this life.
For more on this subject you can also see a video clip on Mormon.org: What happens to people who've never heard of Jesus Christ?