This fire and brimstone, we are informed, is a representation of the torment which shall be suffered by the wicked. It is not actual fire, but it is the torment of the mind; in other words, it is the punishment which the Savior speaks of as being the worm that dieth not and the fire that is not quenched, which shall endure forever.Let us be thankful that there will be but few who partake of this dreadful punishment.
(Joseph Fielding Smith, Doctrines of Salvation, 2:224–25)
