Revelation 9:13-18

And the sixth angel sounded, and I heard a voice from the horns of the golden altar which is before God, one saying to the sixth angel that had the trumpet, Loose the four angels that are bound at the great river Euphrates. And the four angels were loosed, that had been prepared for the hour and day and month and year, that they should kill the third part of men. And the number of the armies of the horsemen was twice ten thousand times ten thousand: I heard the number of them. And thus I saw the horses in the vision, and them that sat on them, having breastplates as of fire and of hyacinth and of brimstone: and the heads of the horses are as the heads of lions; and out of their mouths proceedeth fire and smoke and brimstone. By these three plagues was the third part of men killed, by the fire and the smoke and the brimstone, which proceeded out of their mouths.