Before the explosion of modern translations, the final sentence of Revelation 20:10 roused no one's skepticism. However, the newer versions bring out the fact that the verb here (basanisthēsontai) is plural and is correctly rendered “they will be tormented.” Who are “they”? Does this include the Beast and False Prophet? Does God torment wicked human beings eternally? There are two ways to explain these questions:
1) The Bible denies any idea of men having innate immortality (I Corinthians 15:53; Romans 2:7; I Timothy 6:15-16). These wicked leaders of men in the last days will die and burn to ashes soon after being thrust into the Lake of Fire, their souls and bodies destroyed by Him who can do this in Gehenna fire (Matthew 10:28). This fact would preclude any human from being described as “tormented day and night forever and ever.”
The only group left is the fallen angels—Satan and his demons. But, one may counter, “the devil” in Revelation 20:10 is singular, and “they will be tormented” is plural. How can we reconcile this plural pronoun referring to a singular antecedent?
In this case, “the devil” is used in a figure of speech called metonymy. Technically, it is “the use of the name of one thing for that of another of which it is an attribute or with which it is associated.” More simply, one part of a thing represents the whole. Thus, “the devil” represents in himself all of the group we call demons, devils, fallen angels, or angels who sinned.
A parallel verse, Matthew 25:41, says that sinners will be cast into “the everlasting fire prepared for the devil and his angels.” Jesus intimates that the Lake of Fire's primary purpose is for the punishment of demons, but it will also be used as the means of execution for the wicked among humans, those people who unrepentantly live as demons do.
2) If we understand “they will be tormented” to include the Beast and the False Prophet, we must explain the phrase “forever and ever” (eis tous aiônas tôn aiônôn). Literally, this means “to the ages of the ages” and would seem to imply perpetuity. However, we must be careful with the word aiôn and its various forms. Its range of meaning runs from “a space or period of time” to “a lifetime” to “an age” to “eternity.” As in all such cases, the context must give the sense.
Having rejected the immortality of the soul, we have no recourse but to understand aiôn here in the sense of “as long as conditions exist” or “as long as they live.” Vine's Expository Dictionary of New Testament Words concurs:
AION . . . signifies a period of indefinite duration, or time viewed in relation to what takes place in the period. . . . The phrases containing this word should not be rendered literally, but consistently with its sense of indefinite duration. (p. 43)
Moreover, aiôn can also be rendered as “unto the ages of ages,” “until the eternal age,” or even “up to the vanishing point”! As should be plain, a precise definition of this Greek word proves extremely difficult. Dogmatism on it is not advisable.
Thus, the Beast and False Prophet will be tormented “day and night”—unceasingly—for an indeterminate period until they die, probably within a few minutes or a few hours, which is about as long as a human being can live in a fire. As long as they remain breathing, they will suffer excruciating pain as their just reward, and in an indefinite time, they will pay for their sins with death.