Judah ... fenced cities - Judah, though less idolatrous than Israel, betrayed lack of faith in Jehovah by trusting more to its fenced cities than to Him; instead of making peace with God, Judah multiplied human defenses (Isa 22:8; Jer 5:17; Mic 5:10, Mic 5:11).
I will send ... fire upon ... cities - Sennacherib burned all Judah’s fenced cities except Jerusalem (2Ki 18:13).
palaces thereof - namely, of the land. Compare as to Jerusalem, Jer 17:27.