Revelation 9:14
It said to the sixth angel--the angel who had the trumpet, "Set at liberty the four angels who are prisoners near the great river Euphrates."
Revelation 16:12
The sixth angel poured his bowl into that great river, the Euphrates; and its stream was dried up in order to clear the way for the kings who are to come from the east.
Revelation 7:1
After this I saw four angels standing at the four corners of the earth, and holding back the four winds of the earth so that no wind should blow over the earth or the sea or upon any tree.
Revelation 8:2
Then I saw the seven angels who are in the presence of God, and seven trumpets were given to them.
Revelation 8:6
Then the seven angels who had the seven trumpets made preparations for blowing them.
Revelation 9:15
And the four angels who had been kept in readiness for that hour, day, month, and year, were set at liberty, so that they might kill a third part of mankind.