What does Revelation 20:1 mean?

Satan, also called the Devil, rebelled against God before the dawn of human history (Isaiah 14:12–15). Since then he has opposed God and God's people with cunning and persistence. Revelation 16:13–16 reports that he stirs up international armies to thwart God's purpose for mankind. But after the Lord destroys the massive armies that war against him and casts the beast and the false prophet into the lake of fire, the Devil is incarcerated.

If Satan were allowed to continue his wicked activity, the reign of Christ on the earth would not enjoy peace and righteousness. We read, therefore, that an angel descends from heaven, holding the key to the bottomless pit and a huge chain. The intent, as we learn in the next verse, is to incarcerate the Devil. We do not know whether the chain is figurative or literal, but we know it is effective, and the Devil is about to feel its strength.

Some wonder why God would not choose to cast Satan into the lake of fire immediately, rather than hold him for a thousand years before being released. Most likely, this is part of God's "message" as seen in Revelation. Even after a millennium of goodness and justice, human beings will still choose to reject God and follow Satan. The claim that mankind would follow God "if only" He did something more to win them is a myth, which events in the end times explicitly disprove.