Revelation 9:14
saying to the sixth angel who had the trumpet, "loose the four angels which are bound in the great river Euphrates."
Revelation 16:12
And the SIXTH angel poured out his vial upon the great river Euphrates; and the water thereof was dried up, that the way of the kings of the east might be prepared.
Revelation 7:1
After these things, I saw FOUR ANGELS standing on the four corners of the land, holding the four winds of the land, that the wind should not blow on the land, nor on the sea, nor on any tree.
Revelation 8:2
Then I saw the seven angels who attend in the presence of God; and to them were given seven trumpets.
Revelation 8:6
Then the seven angels who had the seven trumpets, prepared themselves to sound.
Revelation 9:15
and the four angels were loosed, who were prepared for an hour, and a day, and a month, and a year, to slay the third part of men.