1)
What is the reason for the anger?
1.
Malbim: Hashem is angry that they destroyed Yerushalayim and His Kadosh Bayis.
2)
Why does it say "v'Chemah Al Kol Tzeva'am"?
1.
Radak: They will arrange armies, one nation against another, and there will be great bloodshed among them.
2.
Malbim: Chemah is internal, stored hatred. It is greater than Ketzef, which is against the Nochrim who sent to destroy Yerushalayim. Chemah is against the troops that destroyed.
3)
Why does it say "Hecherimam"?
1.
Malbim: The decree against them to be slaughtered cannot be annulled - "Kol Cherem Asher Yacaharam... Lo Yipadeh" (Vayikra 27:28).
