And the sixth angel poured out his bowl upon the great river Euphrates; and its water was dried up, that the way of the kings of the east might be prepared. And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet. For they are the spirits of demons, working miracles, who go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.

Behold, I come as a thief. Blessed is he that watches, and keeps his garments, lest he walk naked, and they see his shame. And he gathered them together into a place called in the Hebrew tongue Armageddon. (Revelation 16:12-16)