1 AND I saw an angel coming down out of heaven, having the key of the abyss, and a great chain in his hand.
Revelation 20:1 Cross References - ABU
Luke 8:31
31 And he besought him that he would not command them to go away into the abyss.
2 Peter 2:4
4 For if God spared not angels, having sinned, but casting them down to hell delivered them over to chains of darkness, reserved unto judgment;
Jude 1:6
6 And angels who kept not their principality, but left their own habitation, he has kept in everlasting chains under darkness, unto the judgment of the great day.
Revelation 1:18
18 and the living one; and I became dead, and behold I am alive forevermore; and I have the keys of death and of the underworld.
Revelation 9:1-2
1 AND the fifth angel sounded; and I saw a star fallen out of heaven to the earth, and there was given to him the key of the pit of the abyss.
2 And he opened the pit of the abyss, and there went up a smoke out of the pit, as the smoke of a great furnace; and the sun and the air were darkened by reason of the smoke of the pit.
Revelation 10:1
1 AND I saw another strong angel coming down out of heaven, clothed with a cloud, and the rainbow was upon his head, and his face was as the sun, and his feet as pillars of fire.
Revelation 18:1
1 AFTER these things I saw another angel coming down out of heaven, having great authority; and the earth was lightened with his glory.