Physical death is the separation of the spirit from the mortal body. The Fall of Adam brought physical death into the world (see Moses 6:48). Because of the Atonement and Resurrection of Jesus Christ, all mankind will be resurrected and redeemed from physical death.
Death is an essential part of Heavenly Father’s plan of salvation (see 2 Nephi 9:6). In order to become like our Eternal Father, we must experience death and later receive perfect, resurrected bodies.
When the physical body dies, the spirit continues to live. In the spirit world, the spirits of the righteous “are received into a state of happiness, which is called paradise, a state of rest, a state of peace, where they shall rest from all their troubles and from all care, and sorrow” (Alma 40:12). A place called spirit prison is reserved for “those who [have] died in their sins, without a knowledge of the truth, or in transgression, having rejected the prophets” (Doctrine and Covenants 138:32). The spirits in prison are “taught faith in God, repentance from sin, vicarious baptism for the remission of sins, the gift of the Holy Ghost by the laying on of hands, and all other principles of the gospel that [are] necessary for them to know” (Doctrine and Covenants 138:33–34). If they accept the principles of the gospel, repent of their sins, and accept ordinances performed in their behalf in temples, they will be welcomed into paradise.
Because of the Atonement and Resurrection of Jesus Christ, physical death is only temporary: “As in Adam all die, even so in Christ shall all be made alive” (1 Corinthians 15:22). Everyone will be resurrected, meaning that every person’s spirit will be reunited with his or her body—“restored to their proper and perfect frame” and no longer subject to death (Alma 40:23; see also Alma 11:44–45).
“Death and Dying,” Encyclopedia of Mormonism
“Families and the Church in God’s Plan,” Handbook 2, 1
“What Happens after We Die?” New Era, March 2013
“The Man Adam,” Liahona, February 1998
“The Purpose of Life” Ensign, April 1993
“Resurrection,” Ensign, April 1991
“Season of Crisis, Season of Growth,” Ensign, September 1987
“Peace in the Shadow of Death,” Ensign, October 1982
“What Mormons Believe About Jesus Christ,” LDS Newsroom
“Death,” Lesson Helps for Teaching Children
“Jesus Raises the Daughter of Jairus”
“Jesus Is Laid in a Tomb”
“Jesus Is Resurrected”
“Sunday Will Come”
“Death Is Swallowed Up in Christ”
“Physical and Spiritual Death”
“The Resurrection of Jesus Christ”
“Bible Story: The Lord has Compassion for Your Pain,” Mormon Channel Daily Archive, episode 658
“Enduring to the Prolonged End—Lillie Woolsey,” Enduring It Well, episode 26