And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand.
All Commentaries on Revelation 20:1 Go To Revelation 20
Andreas of Caesarea
AD 637
an angel. An angel administers such a sentence,it says, in order to show that the devil is both weaker than thèse ministering powers in terms of power and that from the beginning in vain he boldly ruled over all.
Here he narrates the destruction of the devil which had taken place during the Master's passion, in which he who appeared to be strong, having bound us as his spoils, one stronger than he, Christ our God, redeemed us from his hands, condemning him to the abyss. This is shown by the demons calling upon him not to be cast into the abyss.(lk 8:31) chain. He (John) called the restraint of his evil activity chain for our clarification.