Revelation 9:13 Meaning

11And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.

12One woe is past; and, behold, there come two woes more hereafter.

13And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God,

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

15And 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.