This chapter includes the one thousand year period, called the Millennium, when Satan is bound in the bottomless pit for a thousand years (v.1-3), the Second Advent of Christ (v.4-6), followed by a short period of Satan being loosed out of his prison and the battle of Gog and Magog (v.7-10), and finally the Great White Throne Judgment (v.11-15). Satan is cast into the lake of fire where the AntiChrist “beast” and his “false prophet” are. (All bold are my emphases added. Square brackets [ ] indicate meanings of words. King James Version Easy-Reading Bible (KJVER) used.)
1 And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand. 2 And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, 3 And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.
Firstly we read that an angel brings down from heaven the key to the bottomless pit (prison of some kind) (v.1) and the old serpent (the Devil, Satan) is bound there for a thousand years (v.1-3). The ‘angel’ must be stronger than Satan (Matthew 12:29). We’ll see that he is Jesus, who is more powerful than Satan (an angel is not necessarily stronger). After the thousand years bound in prison Satan is loosed for a short period (v.3).
So the question must be asked what does Satan being ‘bound’ mean? That is, Satan is bound “that he should deceive the nations no more”. Before Jesus came to Earth, the first time, all nations were ignorant of the one true God, except for God’s chosen people, Israel. And we read that after Jesus knocked the Apostle Saul (or Paul) off his horse, while he was on the road to Damascus (Acts 9 and 26), Saul asked Him who He was (Acts 9:5; 26:15). And Christ told him that He is Jesus, and that He had chosen him (Saul) to be a minister to preach the gospel to the Gentiles, that is, to the rest of the nations of the world.
Christ tells Saul the mission:
Acts 26:18 To open their eyes, and to turn them from darkness to light, and from the power of Satan to God, that they may receive forgiveness of sins, and inheritance among them which are sanctified [set apart] by faith that is in Me.