Where is Hashem going?
Rashi: From Midas ha'Rachamim to Midas ha'Din.
Radak: This is a metaphor, like "v'Yatza Hashem v'Nilcham ba'Goyim ha'Hem" (Zecharyah 14:3). Hashem will punish them for all their previous sins, and for all the innocent blood that they spilled.
Malbim: To punish the Nochrim who harmed Yisrael.
Which land is discussed?
Rashi: Har Se'ir.
Who are "Harugeha"?
Rashi: They killed Yisrael.
Why does it say "v'Lo Sechaseh Od Al Harugeha"?
Radak: When innocent blood is not avenged, it is as if it is exposed - "Eretz Al Techasi Dami" (Iyov 16:18). It did not mention the other Chamas (extortion), for blood (murder) is the greatest - "v'Nikeisi Damam Lo Nikeisi" (Yo'el 4:21).
Malbim: The land revealed the blood that they spilled in it. It will be exposed to arouse anger to take vengeance for the past. From now and onwards it will not cover up for those who were killed. If a murderer is found, the land will rise to punish him immediately.
