1000 years of peace
Satan or the Red Dragon is under God's control for 1,000 years. Then he will be let loose for a while to test the nations one last time, after which he will never be seen by God's people again.
The period during which Satan is confined and God reigns upon the earth is described in many parts of the Bible, especially Isaiah (e.g. 2:1-5), as being a blessed time of great peace and the rebuilding of the earth after the devastation's of Armageddon.
The saints in this time of a 1000 years came alive again and reigned with God and Jesus.
Check out in the Bible reading below what the some of the saints of God will be doing during those thousand years.
1 And I saw an angel coming down out of heaven, having the key to the Abyss and holding in his hand a great chain. 2 He seized the dragon, that ancient serpent, who is the devil, or Satan, and bound him for a thousand years. 3 He threw him into the Abyss, and locked and sealed it over him, to keep him from deceiving the nations anymore until the thousand years were ended. After that, he must be set free for a short time.
4 I saw thrones on which were seated those who had been given authority to judge. And I saw the souls of those who had been beheaded because of their testimony for Jesus and because of the word of God. They had not worshiped the beast or his image and had not received his mark on their foreheads or their hands. They came to life and reigned with Christ a thousand years. 5 (The rest of the dead did not come to life until the thousand years were ended.) This is the first resurrection. 6 Blessed and holy are those who have part in the first resurrection. The second death has no power over them, but they will be priests of God and of Christ and will reign with him for a thousand years.
7 When the thousand years are over, Satan
will be released from his prison 8 and will go
out to deceive the nations in the four corners of the earth–Gog and
Magog–to gather them for battle. In number they are like the sand on the
seashore. 9 They marched across the breadth of
the earth and surrounded the camp of God's people, the city he loves.
But fire came down from heaven and devoured them. 10
And the devil, who deceived them, was thrown into the lake of burning
sulfur, where the beast and the false prophet had been thrown. They
will be tormented day and night for ever and ever.