Zechariah 14:3-4

Then the LORD will go forth and fight against those nations, as when He fights on a day of battle. In that day His feet shall stand on the Mount of Olives, which lies before Jerusalem on the east; and the Mount of Olives will be split in half from the east to the west by a very large valley, and half of the mountain will move toward the north and half of it toward the south. [Is 64:1, 2]