Jesus said that the unrighteous would go “into everlasting fire prepared for the devil and his angels” (Matthew 25:41). In the book of Jude there is actually an example which shows what everlasting or eternal fire is. “Sodom and Gomorrah, and the cities around them in a similar manner to these, having given themselves over to sexual immorality and gone after strange flesh, are set forth as an example, suffering the vengeance of eternal fire” (Jude 7). The story of the wickedness of Sodom and Gomorrah is recounted in Genesis 19. Lot, the only righteous man in the city, was saved out of it with his family, and “the Lord rained brimstone and fire on Sodom and Gomorrah from the Lord out of the heavens. So He overthrew those cities…and behold, the smoke of the land…went up like the smoke of a furnace…when God destroyed the cities of the plain” (Genesis 19:24-29). Obviously the “eternal fire” which destroyed Sodom is not still burning—it was not quenched or put out; it continued to burn until it had completely done its work of destruction. In the same way the “eternal fire” which will destroy the wicked will destroy them forever. They do not burn eternally; the results are eternal.
This interpretation is verified by the fact that the “everlasting fire” that Jesus spoke about in Matthew 25:41 is “prepared for the devil and his angels.” This means that the fire will do the same thing to unrepentant people that it does to the devil. The fate of Satan is described in Ezekiel 28. The “king of Tyre [Satan]…became filled with violence within and sinned” and so was “cast as a profane thing out of the mountain of God” (vs. 12, 16). God said of him (using His perspective of the future, as if it has already happened), “You defiled your sanctuaries by the multitude of your iniquities…Therefore I brought fire from your midst [this is the eternal fire mentioned in Matthew 25:41]. And I turned you to ashes upon the earth in the sight of all who saw you. All who knew you among the peoples are astonished at you; you have become a horror and shall be no more forever” (vs. 18,19).
Satan will be annihilated eternally; he will not live to be tortured forever in hell, and by no means will he be in charge of hell, directing its torment as he is popularly depicted. As the great instigator of sin, his destruction will be more fearsome than that of any other being (“tormented day and night” Revelation 20:10) but even he will finally be reduced to nothingness and “shall be no more forever.”
Jesus called the “everlasting fire” which completely destroys the devil and the wicked “everlasting punishment” (Matthew 25:41,46). Again, this does not mean punishment that continues forever, but rather punishment that has everlasting results. The apostle Paul made this clear in 2 Thessalonians 1: 7-10: “The Lord Jesus [will be] revealed from heaven with His mighty angels in flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ. These shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power, when He comes in that Day.”
 This is also the meaning of the phrase “unquenchable fire” in Matthew 3:12 and Luke 3:17
 It is obvious that this passage is speaking of Satan, rather than the literal king of Tyre, because 1) He had already talked about the earthly ruler of Tyre in vs. 1-10 under that name “the prince of Tyre.” 2) The “king of Tyre” was “in Eden, the garden of God” (vs. 13), was “the anointed cherub who covers,” “walked back and forth in the midst of fiery stones” (v. 14) and was on “the mountain of God” (v. 15).
 This text which states that the devil “will be tormented day and night forever and ever” appears at first glance to contradict the passage in Ezekial 28. However, it seems to be a shorthand version of Revelation 14:11 which states that “the smoke of their torment ascends forever and ever; and they have no rest day or night, who worship the beast.” It is the smoke, or memorial of their torment, which rises forever. Their torment is a lack of rest, which is transitory, day and night (this phrase refers to a period of time that seems endless but actually does finally end, see Genesis 8:22, Psalms 32:4, 42:3, Revelation 12:10). They do not rest during the time when they “worship the beast and his image” (It does not say that they have no rest who worshiped the beast, as it would if it was referring to a permanent condition which was caused by a previous act). The torment has a permanent result, complete and total destruction, the only trace of which will be the permanent memorial of smoke. This interpretation is confirmed by the fact that Babylon will also be “utterly burned with fire,” “shall not be found anymore,” but “Her smoke [like that of annihilated sinners] rises up forever and ever” Revelation 18:8,21, 19:3.