When Satan is released, he will deceive the nations in order to assemble them to fight against God and his people. God will send fire to burn up the rebellious nations. He will cause Satan to be thrown into the lake of fire for everlasting punishment.

Revelation 20:7-15

7 When the 1,000 years are ended, Satan will be released {God’s angel will release Satan} from the deep pit in which he was imprisoned. 8 He will go out to deceive rebellious people in nations [IDM] all over the earth. These are the nations that the prophet Ezekiel called Gog and Magog. Satan will gather them to fight against God’s people. There will be so many of them fighting against God’s people that no one will be able to count them [SIM], just like no one can count the grains of sand on the ocean shore. 9 They will march over the whole earth and surround the camp of God’s people in Jerusalem, the city that God loves. Then God will send fire down from heaven, and it will burn them up. 10 The devil, who had deceived those people, will be thrown {God’s angel will throw the devil, who had deceived those people} into the lake of burning sulfur. This is the same lake into which both the beast and the false prophet had been thrown {he had thrown both the beast and the false prophet}. As a result, they will continually suffer severely forever.

11 Then I saw a huge white throne on which God was sitting. He was so awesome that the earth and the sky disappeared from his presence completely; they were completely destroyed {God completely destroyed them}. 12 I saw that the people who had died but now lived again were standing in front of the throne. They included people of every social status! The books in which God records what people do were opened {God/God’s angel opened the books in which God records what people do}. Another book was opened {He opened another book}, which is called the Book of Life, in which God has written the names of people who have eternal life. God judged the people who had died and now lived again according to what they had done, just like he had recorded it in the books. 13 The people whose bodies were buried in the sea became alive again in order to stand before God’s throne. Everyone who had been buried on the land (OR, Every person who was waiting in the place where dead people stay) became alive again, in order to stand before the throne. God judged each one of them according to what each one had done. 14 All the unbelievers [PRS, MTY] —those who had been in the place where they waited after they died— were thrown into the burning lake. The burning lake is the place in which people die the second time. 15 The people whose names [MTY] are not in the book, the one where God has written the names of people who have eternal life, were also thrown {◄God/God’s angel► threw them also} into the lake of fire.