When the thousand years are over, Satan will be released from his prison.
References for Revelation 20:7
He will go out to deceive the nations that are at the four corners of the earth—Gog and Magog. He will gather them for battle. Their number is like the sand of the sea.
They came up across the whole earth and surrounded the saints' camp, the city that God loves. But fire came down from heaven and consumed them.
Then the devil, who had deceived them, was thrown into the lake of fire and sulfur, where the beast and the false prophet also were. There painful suffering will be inflicted upon them day and night, forever and always.