The word "earth" is not found until the end of the chapter.
Rev_20:8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
Rev_20:9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them.
(See 2 Thessalonians 1:7-10, and 2 Peter 3:10)
Rev_20:11 And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
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Let's think about this for a moment then, assuming you are the type that likes to think things through.
Revelation 20:1 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.
Look what the text indicates---And I saw an angel come down from heaven. Obviously then, when this angel comes down from heaven he is no longer in heaven but is headed somewhere else instead. Where would he be headed? Would it not be the earth? Would that not be where satan is, meaning after the following events are fulfilled first?
Revelation 12:9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
Revelation 12:12 Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you, having great wrath, because he knoweth that he hath but a short time.
13 And when the dragon saw that he was cast unto the earth, he persecuted the woman which brought forth the man child.
Obviously the chronology is as follows.
Revelation 12:7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
Revelation 12:13 And when the dragon saw that he was cast unto the earth, he persecuted the woman which brought forth the man child.
Revelation 12:17 And the dragon was wroth with the woman, and went to make war with the remnant of her seed, which keep the commandments of God, and have the testimony of Jesus Christ.
Followed by at some point in the future, the fulfillment of the following.
Revelation 20:1 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.
You have been doing interpreting of Scriptures long enough by now to know, that just because something isn't mentioned in a context, such as the earth and context involving the thousand years, that that doesn't always indicate the context does not involve anything not mentioned in the context, in this case the earth. There is such a thing as logically deducing something based on other related Scriptures. I think it tends to fall under interpreting Scripture with Scripture.
It seems to me then, when satan is cast to the earth, he is not then bound at that time if Revelation 12 depicts him waging war instead. When he is bound then, it has to be after he is no longer waging war against the saints in this age. That can't happen until Christ returns in order to put a stop to it at the time. Yet we also see satan must be loosed for a little season.