Overview
When the beast and his prophet were thrown into the fiery lake, the rule of Antichrist and idolatrous Rome ended. Now John's ongoing vision is about to show how the "dragon", Satan himself, meets a similar fate.
The star-angel (of 9:1), who holds the key to the Abyss, seizes the dragon and chains him for a thousand years in the Abyss. Then the martyrs who had died, refusing to receive the mark of the beast, are resurrected, and they reign with Christ on the earth for that millennium. John refers to this resurrection as "the first resurrection" (v.5).
After the thousand years has passed, Satan is released from the Abyss for a short time — but in that brief period he is able to incite the nations (symbolized by "Gog and Magog" of v.8) to "surround the camp of God's people" in Jerusalem ("the city he loves" -v.9). but it's too late — Satan and the nations are defeated by supernatural fire (v.9c). Then he is thrown into the fiery lake forever.
Satan's destruction is followed by the "great white throne" judgment, when each person is "judged according to what he [has] done" (v.13). All whose names are not "written in the Book of life" are "thrown into the lake of fire" (v.15). This is called "the second death" (v.14).
The stage is now set for God to do what He has always planned to do — to create a new heaven and a new earth where God Himself will live with His people.
| 
