In D&C138, a revelation received by the then-president of the Church, Joseph F.
Smith, we read of Jesus’ establishment of preaching the gospel to those who
never received an opportunity in mortality. Notwithstanding, such should not be
taken as evidence that this concept was not known prior to 1918, only that with
D&C 138, it became explicated and more details were revealed. As Richard E.
Bennett noted:
It would be incorrect, however, to conclude
that the doctrine of the gospel being taught to deceased spirits in prison was
not taught in these years. For instance, Elder Erastus Snow said in 1887 that
after his death, Joseph Smith “went and preached [the gospel] to the spirits
who are in prison. And so have all the elders of Israel who have lived
righteous lives, magnified their callings and ministered in their priesthood to
the living, after death, being organized, I believe, as the church here and set
to work in their missionary labors in the spirit world, to carry the gospel to
their fathers whose spirits were in prison.” Salt Lake Herald, 9 October 1887. One of the significant
contributions of Joseph F. Smith’s 1918 vision of the dead was to show that
Christ Himself did not go to the deceased spirits in prison but that He “organized”
His forces to do so. (Richard E. Bennett, Temple
Rising: A Heritage of Sacrifice [Salt Lake City: Deseret Book, 2019], 226
n. 103)