Revelation 20:1

And I saw an agent coming down out of heaven having the key of the abyss and a great chain in his hand.

Revelation 1:18

and he who lives. And I became dead, and behold, I am living into the ages of the ages. Truly. And I have the keys of death and of Hades.

Revelation 10:1

And I saw a mighty agent coming down out of heaven, clothed with a cloud, and the rainbow was upon his head, and his face was like the sun, and his feet like pillars of fire,

Luke 8:31

And they entreated him that he would not command them to to out into the abyss.

2 Peter 2:4

For if God did not spare heavenly agents who sinned, but delivered them up to chains of darkness, having been cast into hell being reserved for judgment,

Jude 1:6

And the heavenly agents who did not keep their own principality, but left their own habitation, he has kept reserved in eternal bonds under darkness for the judgment of the great day.

Revelation 9:1-2

And the fifth agent sounded, and I saw a star fallen from the sky to the earth. And the key of the pit of the abyss was given to him.

Revelation 18:1

And after these things I saw another agent coming down out of heaven having great authority, and the earth was illuminated from his glory.

Treasury of Scripture Knowledge

Summary

And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand.

Bible References

I saw

Revelation 10:1
And I saw a mighty agent coming down out of heaven, clothed with a cloud, and the rainbow was upon his head, and his face was like the sun, and his feet like pillars of fire,
Revelation 18:1
And after these things I saw another agent coming down out of heaven having great authority, and the earth was illuminated from his glory.

Having

Revelation 1:18
and he who lives. And I became dead, and behold, I am living into the ages of the ages. Truly. And I have the keys of death and of Hades.
Revelation 9:1
And the fifth agent sounded, and I saw a star fallen from the sky to the earth. And the key of the pit of the abyss was given to him.
Luke 8:31
And they entreated him that he would not command them to to out into the abyss.

A great

2 Peter 2:4
For if God did not spare heavenly agents who sinned, but delivered them up to chains of darkness, having been cast into hell being reserved for judgment,
Jude 1:6
And the heavenly agents who did not keep their own principality, but left their own habitation, he has kept reserved in eternal bonds under darkness for the judgment of the great day.

General references

Matthew 8:31
And the demons besought him, saying, If thou cast us out, allow us to go away into the herd of swine.
Matthew 12:29
Or how can any man enter into the house of the strong man, and plunder his goods, unless he first binds the strong man? And then he will plunder his house.
Mark 3:27
But no man, having enter into the house of the strong man, can plunder his goods unless he first binds the strong man, and then he may plunder his house.
Luke 11:22
but when a stronger than he comes, after defeating him, he takes away his full armor in which he trusted, and divides his booty.