Revelation 16:12
And the sixth angel poured out his cup on the great river Euphrates; and its water was dried up, that the way of the kings of the east might be prepared.
Revelation 9:14
saying to the sixth angel, who had the trumpet: Loose the four angels that are bound at the great river Euphrates.
Revelation 7:2
And I saw another angel ascending from the east, having the seal of the living God: and he cried with a loud voice to the four angels, to whom it was given to hurt the earth and the sea,
Revelation 11:14
The second woe is past: behold, the third woe comes quickly.
Revelation 17:15
And he said to me: The waters which you saw, where the harlot sits, are peoples and multitudes and nations and tongues.