What is the meaning of "Lo Alman"?
Rashi: [Yisrael] did not forget to take its vengeance.
Radak: [Yisrael] is not like a widow whose husband died and she is permanently abandoned from him. Yisrael's Husband is alive. If He abandoned her in exile, He will return to her and punish her enemies.
Malbim: Yisrael was not widowed from their G-d; Hashem will wage their quarrel.
Whose land is full of sin?
Rashi: The Bavliyim's land.
Why does it say "mi'Kedosh Yisrael"?
Mahari Kara: They angered the Kadosh of Yisrael.
Radak: [Bavel is full of sin] from evil that they did to Yisrael, Hashem's nation.
Radak citing Targum Yonasan: [They are Chayav Misah] due to the word of the Kadosh of Yisrael.
Malbim: They sinned against the Kedushah of the Mikdash, and used the Kelim of the Mikdash. This is why Belshatzar was killed!