Revelation 9:11

9:11 They have as king over them the angel of the abyss, whose name in Hebrew is Abaddon, and in Greek, Apollyon.

Revelation 11:7

11:7 When they have completed their testimony, the beast that comes up from the abyss will make war on them and conquer them and kill them.

Revelation 20:1

The Thousand Year Reign

20:1 Then I saw an angel descending from heaven, holding in his hand the key to the abyss and a huge chain.

Revelation 9:1-2

9:1 Then the fifth angel blew his trumpet, and I saw a star that had fallen from the sky to the earth, and he was given the key to the shaft of the abyss. 9:2 He opened the shaft of the abyss and smoke rose out of it like smoke from a giant furnace. The sun and the air were darkened with smoke from the shaft.

Revelation 17:8

17:8 The beast you saw was, and is not, but is about to come up from the abyss and then go to destruction. The inhabitants of the earth – all those whose names have not been written in the book of life since the foundation of the world – will be astounded when they see that the beast was, and is not, but is to come.

Revelation 20:3

20:3 The angel then threw him into the abyss and locked and sealed it so that he could not deceive the nations until the one thousand years were finished. (After these things he must be released for a brief period of time.)