Revelation 20:3, 7-8

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.

When the thousand years are over, Satan will be released from his prison and will go out to deceive the nations in the four corners of the earth—Gog and Magog—and to gather them for battle. In number they are like the sand on the seashore.