Which city was made into a heap?
Rashi: Har Se'ir.
Radak: Many cities of Goyim will be destroyed at that time.
Why does it say "Kiryah Vetzurah l'Mapelah"?
Radak: The matter is repeated in different words to strengthen it.
Malbim: This is a greater wonder. Not only will a city become a rock-pile in a moment - also a fortified walled city will suddenly fall.
What is the meaning of "Armon Zarim me'Ir"?
Rashi: Due to the sin that they did in Your city - they destroyed it - You will make their castles ruins that will never be rebuilt.
Radak: This refers to Bavel, which was like a castle to all Nochri cities; they are called Zarim and Nochrim. It will never be rebuilt 1 .
Malbim: From cities of Yisrael, You removed the castles that Nochrim established there, that they will never be rebuilt.
Radak (13:19): Daryavesh destroyed the old Bavel, and built another city in that valley; it is called Bavel nowadays.
