And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little while.
All Commentaries on Revelation 20:3 Go To Revelation 20
Augustine of Hippo
AD 430
set a seal upon him. that it was designed to keep it a secret who belonged to the devil's party and who did not. For in this world this is a secret, for we cannot tell whether even the man who seems to stand shall fall, or whether he who seems to lie shall rise again.