Revelation 9:11

For they had a king over them, the angel of the bottomless pit, whose name, in the Hebrew language, is Abaddon; and in the Greek, he has the name Apollyon.

1 John 4:4

You are of God, little children, and have overcome them; because he is greater, who is with you, than he who is with the world.

1 John 5:19

We know that we are of God, and that the whole world lies under the wicked one.

Revelation 9:1-2

And the fifth angel sounded; and I saw a Star fall from the heaven to the earth; and there was given to him the key of the bottomless pit.

Revelation 12:9

And thus the great dragon was cast out; even the old serpent called the Devil, and Satan, who deceives the world, was cast out to the earth; and his angels were cast out with him.

Treasury of Scripture Knowledge

Summary

And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.

The angel

Bible References

They had

Revelation 12:9
And thus the great dragon was cast out; even the old serpent called the Devil, and Satan, who deceives the world, was cast out to the earth; and his angels were cast out with him.
1 John 4:4
You are of God, little children, and have overcome them; because he is greater, who is with you, than he who is with the world.
1 John 5:19
We know that we are of God, and that the whole world lies under the wicked one.

The angel

Revelation 9:1
And the fifth angel sounded; and I saw a Star fall from the heaven to the earth; and there was given to him the key of the bottomless pit.