Revelation 16:14-16

14For they are demonic spirits, performing signs, who go abroad to the kings of the whole world, to assemble them for battle on the great day of God the Almighty.

15("Behold, I am coming like a thief! Blessed is the one who stays awake, keeping his garments on, that he may not go about naked and be seen exposed!")

16And they assembled them at the place that in Hebrew is called Armageddon.