What about those who were never baptized?
Latter-day Saints believe that baptism is essential, but we also believe God is completely fair and merciful. Many people never had a true chance in this life to hear the gospel or receive baptism by proper authority. Because of that, God has provided a way for them to receive the blessings of baptism. References: Baptisms for the Dead; Baptism; John 3:5.
We believe the gospel is preached in the spirit world, and in temples living members may be baptized by proxy for the dead. These ordinances are offered, not forced. Each person remains free to accept or reject them. References: Baptisms for the Dead; Spirit World; Doctrine and Covenants 138:31–34; 1 Corinthians 15:29.
The doctrine of The Church of Jesus Christ of Latter-day Saints on the salvation of little children can be summarized in a single verse of scripture: “All children who die before they arrive at the years of accountability are saved in the celestial kingdom of heaven” (Doctrine and Covenants 137:10).