When will Hashem return the captivity of Yehudah and Yerushalayim?
Radak: It is in the days of Mashi'ach.
Malbim: It is in the end of days.
Why does it specify Yehudah and Yerushalayim? Will not all of Yisrael return?
Radak: It mentions Yehudah, because Mashi'ach will be from Yehudah. It mentions Yerushalayim, for it is the capitol, and the war of Gog and Magog will be there.
Malbim: Also the 10 tribes will return; Yehudah is primary in the eyes of Hashem.
It is written Ashuv, and we pronounce it Ashiv!
Radak: The Kesiv is an expression of rest and serenity, like "v'Shav Hashem Elokecha Es Shevuscha" (Devarim 30:3). The pronunciation is an expression of returning [something - Po'el Yotzei].