What are "Arei Ma'uzo"?
Rashi: They are cities of Yisrael.
What is "ka'Azuvas ha'Choresh veha'Amir"?
Rashi: They are abandoned like a forest, which is desolate of people. The Targum of b'Ya'ar (Devarim 19:5) is b'Chorsha. Also Amir is a forest, a place of trees, like the cities of the Emori'im. In the days of Yehoshua they left them desolate like a forest and fled, "due to Bnei Yisrael", and Eretz Yisrael was desolate.
Radak: Azuvah is a noun, like "v'Rabah ha'Azuvah" (6:12). It has the same grammatical form as Meluchah. Arei Ma'uzo will be abandoned due to the enemy, like the abandonment of the Choresh and Amir due to their height and small number, like it says above "Shenayim Sheloshah Gargarim b'Rosh Amir" (6).
Malbim: This is the forest in Har Efrayim mentioned in Yehoshua (17:18) "Ki Har Yihyeh Lach Ki Ya'ar Hu u'Vere'oso
Why does it say "Asher Azvu Mipnei Bnei Yisrael"?
Radak: It is like the Kena'ani abandoned due to Bnei Yisrael. "Ka'Azuvas" applies also to this. Many of the seven nations fled and abandoned their cities when Yisrael came to the land. Vayikra Rabah 17:6 says that the Kena'ani fled to Africa. Some say that the Prizi went away. So Yisrael abandoned even the strong cities due to Melech Ashur. Perhaps it says about them "Alah
He explains Azivah to be helping, like "Azov Ta'azov Imo" (Shemos 23:5, Rashi there). (PF)
What will be desolate?
Radak: The land will be desolate without residents.
Malbim: The cities of Efrayim,
