Revelation 20:7

New King James Version

Now when the thousand years have expired, Satan will be released from his prison

Cross References

Revelation 20:2

He laid hold of the dragon, that serpent of old, who is the Devil and Satan, and bound him for a thousand years;

Revelation 9:15

So the four angels, who had been prepared for the hour and day and month and year, were released to kill a third of mankind.