'Strongholds' in the Bible

He broke down their strongholds and devastated their cities. The land and everything in it was frightened at the sound of his roaring.

"This is what you must say to them, 'This is what the sovereign Lord says: As surely as I live, those living in the ruins will die by the sword, those in the open field I will give to the wild beasts for food, and those who are in the strongholds and caves will die of disease.