Revelation 9:14
say to the sixth angel who had the trumpet, "Release the four angels that are bound at the great river Euphrates."
Revelation 16:12
The sixth emptied his bowl upon the great river Euphrates, and its waters dried up to make the way ready for the kings from the east.
Revelation 7:1
After that I saw four angels standing at the four corners of the earth holding back the four winds of the earth, so that no wind should blow on the earth or on the sea or on any tree.
Revelation 8:2
Then I saw the seven angels who stood before God, and seven trumpets were given to them.
Revelation 8:6
Then the seven angels with the seven trumpets prepared to blow them.
Revelation 9:15
Then the four angels who were held in readiness for that hour and day and month and year were let loose to kill one third of mankind.