Revelation 20:7 And when the thousand years are ended, Satan will be released from his prison and will come out to deceive the nations that are at the four corners of the earth, Gog and Magog, to gather them for battle; their number is like the sand of the sea. And they marched up over the broad plain of the earth and surrounded the camp of the saints and the beloved city, but fire came down from heaven and consumed them, and the devil who had deceived them was thrown into the lake of fire and sulfur where the beast and the false prophet were, and they will be tormented day and night forever and ever.
Why is Satan imprisoned for a time and then released? Why not cast him into hell before the 1,000 years? Joseph A. Seiss writes, “God uses even the wickedest of beings, and overrules the worst depravity, to his own good and gracious ends. He allows Satan liberty, and denies him liberty, and gives him liberty again, not because the Devil or the Devil’s malice is necessary to him, but to show his power to bring good out of evil, to make even the worst of creatures praise him, and to turn their very wickedness to the furtherance of the purposes they would fain defeat” Phillips, Rob. The Searcher’s Guide to the Apocalypse: A Verse-by-Verse Quest to Understand the Book of Revelation .
Perhaps Satan’s release serves as final proof that the heart of man is desperately wicked and can be changed only by God’s grace. Imagine the tragedy of this revolt: People who have been living in a perfect environment, under the perfect government of God’s Son, finally show their true colors and rebel against the King. Their obedience during the 1,000 years is false humility and feigned submission, not true faith in the Messiah. “This rebellion proves that a rule of perfect law cannot change the human heart; sinners would rather follow Satan,” writes Warren Wiersbe
Many commentators say that Satan is loosed so that those who grow up during the millennium, under the perfect and righteous reign of Christ, have the chance to choose between good and evil, between God and Satan. Satan is loosed and immediately plays the tempter’s role. Though bound in prison for a thousand years, he is as vile and as subtle, as merciless and as ruthless, as diabolical and as evil, as he was in the beginning. He has not changed. And, sadly, mankind has not changed either.
But who are these followers of Satan? Premillennialists like J.F. Walvoord and R.B. Zuck say they are survivors of the tribulation. They enter the millennium in their natural bodies, bear children and repopulate the earth (Isa. 65:18–25). Under ideal circumstances in which every person knows about Jesus Christ (cf. Jer. 31:33–34), many will outwardly profess faith in Christ without actually placing faith in Him for salvation. The shallowness of their professions becomes apparent when Satan is released. The multitudes that follow Satan are evidently those who have never been born again in the millennial kingdom