Malbim: It is after the Nevu'ah that Hashem will cause the lottery to fall on Yerushalayim, and not on Rabas Bnei Amon, this is astounding. Are Bnei Amon more virtuous than Yisrael?! Therefore, Hashem reveals Yerushalayim's sins due to which He was angry at them, and adds that there were not Tzadikim among them.