Joel 2, 3

A fearsome battle is described by the prophet Joel such as has never been. Its epicenter will be the Valley of Jehoshaphat, possibly Armageddon. Revelation describes a similar conflict in the valley of Megiddo. I stood overlooking this valley and grimaced at the thought of what the Bible describes will happen there. Regardless where this conflict will happen, the important point to remember is that God will protect HIS OWN PEOPLE from its devastation as He judges the nations for their rebellion against Him.

… The earth and the heavens will tremble.
But the Lord will be a refuge for his people,
    a stronghold for the people of Israel. [Joel 3:16b]