What is the significance of "v'Chalah Api"?
Radak: This is like "Chitzai Achaleh Bam" (Devarim 32:23; His arrows will be finished, and they will not be finished).
Malbim: Via the first third, who will die in the city, My external anger will cease.
What is the meaning of "va'Hanichosi Chamasi Bam"?
Rashi: When I take vengeance on them, My anger will rest, and My Ru'ach will not pain Me.
Radak: After I finish My anger, I will rest from My vengeance, for it will be great.
Malbim: Via the second third, who will fall around the city, I will cease from My internal anger. This is not from His Midah of mercy, which does not arouse all His anger. Rather, it is due to His Kin'ah, for the honor of the Mikdash - "Ya'an Es Mikdashi Timeisa" (11).
Why does it say "v'Hinechamti"?
Rashi: I will be consoled for the pain that they pained Me. Radak - this is Hispa'el. It should be Hisnechamti, like "va'Yema'en Lehisnachem" (Bereishis 37:35). The Nun has a Segol in place of a Patach, and it has a Dagesh in place of the missing Sav.
Radak citing Targum Yonasan: I will finish [My anger].
Malbim: Via the last third - "v'Zarisi Es Kol She'erisech l'Chol Ru'ach" - "I will be consoled."
What is the significance of knowing that Hashem spoke?
Malbim: They will know that the punishment is via Hashgachah