What will result from Hashem's mercy for Yakov?
Rashi: He will guard the promise 1 to redeem them from Bavel.
Radak: The time of Churban Bavel will come soon, for this will be salvation for Yisrael.
Malbim: The redemption of Yisrael is either via Hashem's mercy, or their good deeds. If they merit, they do not need mercy (refer to 14:1:2:2). If not, He will redeem them amidst mercy over their subjugation, and lest they perish among the nations. "Yakov" are the masses, who are not at such a high level.
Why does this depend on mercy? Hashem guards His promises due to Emes! Perhaps He will fulfill it now due to mercy, like Radak says. (PF)
What is the meaning of "u'Vachar Od b'Yisrael"?
Rashi: In the future, He will totally redeem them.
Malbim: Just like He chose them earlier to be "Mamleches Kohanim v'Goy Kadosh" (Shemos 19:6), so He will choose them. "Yisrael" are those who are at a high level.
What is the meaning of "v'Hinicham Al Admasam"?
Malbim: He will give to them respite from all enemies and afflicters. Perforce, He will need to abolish the kingship of Kasdim beforehand.
Why will converts accompany them?
Malbim: It will be due to their serenity and success.
What is "v'Nispechu"?
Rashi: They will be added. The same applies to "Sefacheni Na", "me'Histape'ach b'Nachalas Hashem" (Shmuel I, 2:36, 26:19).
Radak #1: Converts will attach to them to see them, for Churban Bavel was their salvation. They will admit that the Churban was due (in order) to save Yisrael, for they were overly evil to Yisrael - "Katzafti Al Ami
Radak: We do not find verses saying that people converted. Also, "v'Lakchum Amim
