Revelation 20:1-7 NIV
And I saw an angel coming down out of heaven, having the key to the Abyss and holding in his hand a great chain. He seized the dragon, that ancient serpent, who is the devil, or Satan, and bound him for a thousand years. 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.
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 about Jesus and because of the word of God. They had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ a thousand years. (The rest of the dead did not come to life until the thousand years were ended.) This is the first resurrection. Blessed and holy are those who share 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.
When the thousand years are over, Satan will be released from his prison
NIV: New International Version