Revelation 9:14-16; Revelation 16:12

14 Saying to the sixth angel which had the trumpet, Loose the four angels which are bound in the great river Euphrates.

15 And the four angels were loosed, which were prepared for an hour, and a day, and a month, and a year, for to slay the third part of men.

16 And the number of the army of the horsemen were two hundred thousand thousand: and I heard the number of them.

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.