In his vision of the celestial kingdom Joseph Smith gained a significant doctrinal insight concerning this latter group of people. In it the doctrine of salvation for the dead-those who were not able to he fully accountable in mortality-was taught him. “Thus came the voice of the Lord unto me saying: All who have died without a knowledge of this gospel, who would have received it if they had been permitted to tarry, shall be heirs of the celestial kingdom of God; also all that shall die henceforth without a knowledge of it, who would have received it with all their hearts, shall be heirs of that kingdom” (D&C 137:7-8, italics added).