'Fortresses' in the Bible

He will be their peace.When Assyria invades our land,when it marches against our fortresses,we will raise against it seven shepherds,even eight leaders of men.

I will remove the cities of your landand tear down all your fortresses.

They will lick the dust like a serpent,Like reptiles of the earth.They will come trembling out of their fortresses;To the Lord our God they will come in dreadAnd they will be afraid before You.