Why will the nations then sing the praises of Yisrael?
Rashi: Because as they well know, in spite of all the long and endless persecutions, Yisrael have remained faithful and clung to Hakadosh-Baruch-Hu throughout never forsaking Him.
Rashbam: The nations should praise (not Yisrael, but) Hashem due to His people - and believe in Him, 1 because His kindness to His people exceeds His kindness to all other nations. 2
Seforno: The Pasuk means that both the nations and Yisrael should praise Hashem 3 - the nations should acknowledge that He is Just - and that there is no injustice in Him, and Yisrael should give thanks and the voice of song. 4
Targum Onkelos, Targum Yonasan, Da'as Zekenim, Hadar Zekenim (in Pasuk 41), Rosh: Because Yisrael are fortunate in that Hashem punishes those who afflict them.
Rashbam: Because if they will believe in Him and worship Him, He will extend His kindness to them too.
Rashbam: As the Pasuk writes in Tehilim, 117:1.
Seforno: When "He takes revenge from them" - as the Pasuk writes in Tehilim, 67:5.
Seforno: When "He atones for them."
Which two acts of revenge is the Pasuk referring to?
Rashi: "Dam Avadav Yikom" refers to vengeance for the nations' murder of Yisrael, and "ve'Nakam Yashiv le'Tzarav", for taking their property by force. 1
Rashi: As the Navi states in Yo'el 4:19 and Ovadyah, 1:10.
What is the meaning of "Vechiper Admaso Amo"?
Rashi: It means that Hashem will appease His land and His people' 1 over all the Tzaros that they suffered at the hand of the enemy.
Seforno: It means that Hashem will atone for the land 2 and for the people, 3 for the Chilul Hashem that they caused with their evil deeds, and He is now returning His Shechinah in their midst. 4
Rashbam, Hadar Zekenim and Riva: It means that He will cleanse the blood of His people from the land, by spilling the blood of the enemy. 5
Rosh and Da'as Zekenim: It means that Yisrael will atone, by taking revenge from Edom.
Targum Onkelos and Targum Yonasan: It means that Hashem will atone on His land.
Kesuvos 111a: We learn via a Gezeirah Shavah "ve'Chiper Admaso Amo" and "Mizbach Adamah" - Yisro, Sh'mos, 20:21, that if someone is buried in Eretz Yisrael, it is as if he is buried underneath the Mizbe'ach.
Yerushalmi Kil'ayim, 9:5: When Meisim would arrive from Chutz la'Aretz to Eretz Yisrael, they would place some earth from Eretz Yisrael on the coffin before burying them, in order to atone for them - because the Torah writes "Vechiper Admaso Amo". 6
Oznayim la'Torah (citing the Tanchuma and Midrash Rabah in Eikev): It refers to the fruit of Eretz Yisrael, which atone for Yisrael in the form of Bikurim, T'rumos, Ma'asros and Menachos.
Rashi: When His people are comforted, the land is comforted too. See Tehilim, 85:2. See also Sifsei Chachamim.
When it lay desolate from all that was done in it.
Oznayim la'Torah: As if the Torah had written "Admaso ve'Amo".
Seforno: As the Navi writes in Yeshayah, 52:8.
Rashbam: As the Torah writes in Mas'ei Bamidbar, 35:33 - "ve'ha'Aretz Lo Yechupar ? Ki Im be'Dam Shofcho". Oznayim la'Torah: Hence He will first gather the guilty nations in Eretz Yisrael.
See Torah Temimah, citing the Yerushalmi (Ibid.), and note 88.
QUESTIONS ON RASHI
Rashi writes that "ve'Nakam Yashiv le'Tzarav" refers to revenge for taking their property as it writes in Yo'el 4:19. But that Pasuk concludes "Asher Shafchu Dam Naki"?
Riva (citing R. Tam of Orleans): The Gemara in Bava Kama 119a states that, if one steals a P'rutah, it is as if he has taken the soul of his victim. Consequently, the Pasuk in Yo'el is referring to the robbery of the B'nei Yehudah's property as murder.
