From The Encyclopedia of Mormonism
Author: Parsons, Robert J.
In Latter-day Saint doctrine the "spirit prison" is both a condition and a place within the postearthly spirit world. One "imprisons" himself or herself through unbelief or through willful disobedience of God. In such circumstances, one's opportunities in the afterlife will be limited. Those who willfully rebel against the light and truth of the gospel and do not repent remain in this condition of imprisonment and suffer spiritual death, which is a condition of hell (Alma 12:16-18; D&C 76:36-37). Furthermore, since a fulness of joy is not possible without the resurrected body, the waiting in the spirit world for the resurrection is a type of imprisonment (D&C 45:17;93:33-34;138:16, 17, 50). However, through the Atonement of Jesus Christ all have a promise of resurrection, and thus of eventual release from this type of spirit prison, although the unrepentant will still be imprisoned by their unbelief (see Damnation).
Another more far-reaching definition of "spirit prison" is hell. In this sense, spirit prison is a temporary abode in the spirit world of those who either were untaught and unrighteous, or were disobedient to the gospel while in mortal life (cf. Alma 40:11-14; D&C 138:32).
As part of his redemptive mission, Jesus Christ visited the spirit world during the interlude between his own death and resurrection, and "from among the righteous, he organized his forces and appointed messengers, clothed with power and authority, and commissioned them to go forth and carry the light of the gospel to them that were in darkness"-in other words, to the spirits in prison (D&C 138:30; cf. 1 Pet. 3:18-20;4:6). Thus, the gulf between paradise and hell that is spoken of in Jesus' parable of the rich man and Lazarus (Luke 16:19-31) was bridged by the Savior's ministry in the spirit world. This bridging allows interaction among the righteous and wicked spirits to the extent that the faithful present the gospel to "those who had died in their sins, without a knowledge of the truth, or in transgression, having rejected the prophets" (D&C 138:32). Latter-day Saints believe that preaching the gospel in the spirit world continues today and will continue until every soul who wishes to do so and repents properly will be released from such imprisonment.
Repentance of imprisoned spirits opens the doors of the prison, enabling them to loose themselves from the spiritual darkness of unbelief, ignorance, and sin. As they accept the gospel of Jesus Christ and cast off their sins, the repentant are able to break the chains of hell and dwell with the righteous in paradise. [See also Salvation of the Dead.]
Pratt, Orson. "Deity; The Holy Priesthood." In Masterful Discourses and Writings of Orson Pratt, N. B. Lundwall, comp., pp. 260-68. Salt Lake City, 1946.
ROBERT J. PARSONS