1 Then I saw an angel coming down from heaven with the key of the abyss and a great chain in his hand.
Revelation 20:1 Cross References - Williams
Luke 8:31
31 Then they continued to beg Him not to order them to go off to the bottomless pit.
2 Peter 2:4
4 For if God did not spare angels when they sinned, but hurled them down to Tartarus and committed them to dark dungeons to await their doom,
Jude 1:6
6 And angels, who did not preserve their original rank but left their proper home, He has kept in everlasting chains under darkness, for the day of judgment,
Revelation 1:18
18 yea, the ever-living One. I once was dead, but now I live forever and ever. I carry the keys of death and the underworld.
Revelation 9:1-2
1 Then the fifth angel blew his trumpet, and I saw a star that had fallen from the sky upon the earth. To this angel the key to the pit of the abyss was given,
2 and he opened the pit of the abyss, and smoke like the smoke of a huge furnace puffed up out of the pit, and the sun and the air were darkened by the smoke from the pit.
Revelation 10:1
1 Then I saw another mighty angel coming down from heaven. He was clothed in a cloud, with a rainbow over his head; his face was like the sun, his legs were like pillars of fire,
Revelation 18:1
1 After this I saw another angel coming down from heaven. He had great authority and the earth was lighted up with his splendor.