Revelation 9:1

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.

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 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.)