Chapter 20 presents the seventh and final vision of judgment. While this chapter produces some of the most bizarre interpretations concerning the 1000 year period and the unbinding of Satan, it is rather simple and easy to understand given two premises:
1) The 1000 years is the supernatural equivalent to the 1260 days/42 months. It is an indefinite period. In other words, the 1000 years is occurring now. The spiritual realm does not operate using a days/months/years timeline as our natural world does, so it makes perfect sense to have a symbolic parallel to define this period.
2) Satan was "bound" by Jesus Christ at His first advent. This has been made quite clear in the Scriptures:
Or
how can one enter a strong man’s house and plunder his goods, unless he
first binds the strong man? And then he will plunder his house. (Matt. 12:29)
John 12:31:
Now is the judgment of this world; now the ruler of this world will be cast out.
It is important to understand here that
cast out,
cast down, and
bound all mean the same thing: that a limitation has been imposed on Satan and his angels. Like the
fall of man, or Babylon being
fallen, it describes a degenerate state of being. Because of this we have been given power over them:
Then He called His twelve disciples together and gave them power and authority over all demons, and to cure diseases. (Luke 9:1)
It would benefit the reader here to review Chapter 12 as it describes the same process shown here; that is, the casting down of Satan following the First Advent of Jesus Christ.
So the great dragon was
cast out, that serpent of old, called the Devil and Satan, who deceives
the whole world; he was cast to the earth, and his angels were cast out
with him. (v. 9)
We remember a similar situation described in the Book of Job:
And the Lord said to Satan, “Behold, all that he has is in your power; only do not lay a hand on his person.” (1:12)
Satan was already on the earth in those days. He was given as certain amount of power over Job, but was imposed with a limitation: he was not allowed to kill Job. And we remember from the Bowl and Trumpet analyses that the 6th of these are marked by unbound demonic activity; this is the same point when the Two Witnesses are killed.
Chapter 20 begins at the start of the Gospel Age, when Satan is bound:
Then I saw an angel coming down from heaven, having the key to the bottomless pit and a great chain in his hand. He laid hold of the dragon, that serpent of old, who is the Devil and Satan, and bound him for a thousand years; (vv. 1-2)
We are also told that he will be released:
But after these things he must be released for a little while. (v.3)
Then in verses 4 through 6 we find a parenthetical aside wherein the saints/God's people are shown in Heaven:
And I saw thrones, and they sat on them, and judgment was committed to them. Then I saw
the souls of those who had been beheaded for their witness to Jesus and
for the word of God, who had not worshiped the beast or his image, and
had not received his mark on their foreheads or on their hands. And they lived and reigned with Christ for a thousand years. (v.4)

Again, this 1000 years is the same time period as the 1260 days tribulation, only in the supernatural realm. This period of time is synchronous to the Fifth Seal period--
the long passage of time--when the saints in Heaven ask "How long, O Lord?"
We then read that these saints are of the First Resurrection:
But the rest of the dead did not live again until the thousand years were finished. This is the first resurrection.
There are two deaths: the body is the first, and the death of the soul is the second. The rest of the dead, the unsaved, or those with the mark, will live again to face the second death at the Throne of Judgment. In the above verse, "This is the first resurrection" refers back to the saints mentioned first.
Blessed and holy is
he who has part in the first resurrection. Over such the second death
has no power, but they shall be priests of God and of Christ, and shall
reign with Him a thousand years. (v.6)
So:
1) First death: death of the body, both saved and unsaved.
2) First resurrection: souls of the saints/saved. Reign with Christ during the 1000 years.
3) Second resurrection: at the end of the 1000 years; souls of unsaved for judgment.
4) Second death: souls of unsaved only.
The beginning in Verse 7, the focus is shifted back to earth when Satan is unbound:
Now when the thousand years have expired, Satan will be released from his prison and will go out to
deceive the nations which are in the four corners of the earth, Gog and
Magog, to gather them together to battle, whose number is as the sand of the sea. (vv.1-2)
Satan being
released from his prison means that he is
unbound, or the limitations have been removed.
And again we read of this final battle, typically referred to as "Gog and Magog"--although this refers more to the nations rather than a battle itself. This is the same as "Armageddon." In the last article it was asked whether this final battle was against Jesus' Second Coming directly, or against His people just prior to His Second Coming.
They went up on the
breadth of the earth and surrounded the camp of the saints and the
beloved city. And fire came down from God out of heaven and devoured
them. (v.9)
Verse 9 seems to give the make the latter the most sensible reading here. Satan's army surrounds the saints' camp and the beloved city, "Jerusalem," the Bride of Christ.
The battle is decided in short order, then the devil joins in the lake of fire those who served him.
The devil, who deceived them, was cast into the lake of fire and brimstone where the beast and the false prophet are. And they will be tormented day and night forever and ever. (v.10)
That is it for the natural world. Next comes the Great White Throne of Judgment, Verses 11-15:
Then I saw a great white throne and Him who
sat on it, from whose face the earth and the heaven fled away. And
there was found no place for them.
The Book of Life:
And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books.
The interesting thing in the above verse it that it indicates that those unsaved being judged will face varying levels of punishment, according to their works. Everyone throughout history is brought before the Throne of God:
The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works.
This final judgment, being cast into the lake of fire is the second death: the death of the soul--that part the saints will not face mentioned in Verse 6.
Then Death and Hades were cast into the lake of fire. This is the second death. And anyone not found written in the Book of Life was cast into the lake of fire.
Next, in Chapter 21, John will describe the afterlife.