'Fenced Cities' in the Bible

Declare ye in Judah, and cause it to be heard in Jerusalem, and say, ... and blow the trumpet in the land, cry aloud and say, Assemble yourselves, and let us enter into the fenced cities.

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

And 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 were amongst the cities of Judah, the fenced cities that were left.