'Fenced Cities' in the Bible

Declare ye in Judah, and publish in Jerusalem; and say, Blow ye the trumpet in the land: cry, gather together, and say, Assemble yourselves, and let us go into the defenced cities.

And they shall eat up thine harvest, and thy bread, which thy sons and thy daughters should eat: they shall eat up thy flocks and thine herds: they shall eat up thy vines and thy fig trees: they shall impoverish thy fenced cities, wherein thou trustedst, with the sword.

Why do we sit still? assemble yourselves, and let us enter into the defenced cities, and let us be silent there: for the LORD our God hath put us to silence, and given us water of gall to drink, because we have sinned against the LORD.

When the king of Babylon's army fought against Jerusalem, and against all the cities of Judah that were left, against Lachish, and against Azekah: for these defenced cities remained of the cities of Judah.