What are "Chol Gederosav"?
Rashi: They are all the walls that he built in Yerushalayim.
Radak: They are all the fences that You put for him via Your help - "Lo Yasi Oyev Bo" (verse 23), You did not let an enemy harm him. You breached those fences and fortresses, and made them ruins [and enemies came - verse 42].
Malbim: The verse depicts 1 that the king made a wall around his country to block foreigners from his nation, and fortresses. You breached them, and foreigners entered his land.
Malbim: Really, the king does not make a wall; he has guards and soldiers by the border cities.
What are "Mivtzarav"?
Rashi: They are Har ha'Bayis and Metzudas Tziyon.
Malbim: They are fortresses to take refuge in them at a time of war. Your destroyed them, and there is no fortress to take refuge in from the enemy.
