בְּסֹדָם֙ אַל־תָּבֹ֣א נַפְשִׁ֔י בִּקְהָלָ֖ם אַל־תֵּחַ֣ד כְּבֹדִ֑י כִּ֤י בְאַפָּם֙ הָ֣רְגוּ אִ֔ישׁ וּבִרְצֹנָ֖ם עִקְּרוּ־שֽׁוֹר׃
Ne t’associe point à leurs desseins, ô mon âme! Mon honneur, ne sois pas complice de leur alliance! Car, dans leur colère, ils ont immolé des hommes et pour leur passion ils ont frappé des taureaux.
Rashi
בן יצהר בן קהת בן לוי [KORAH] THE SON OF IZHAR, THE SON OF KOHATH, THE SON OF LEVI — It does not, however, make mention of Levi being “the son of Jacob”, because he (Jacob) offered prayer for himself that his name should not be mentioned in connection with their (the Korahites') quarrels, as it is said, (Genesis 49:6) “with their assembly, my glory. be thou not united”. And where is his name mentioned in connection with Korah? In the passage in Chronicles where their (the Korahites’) genealogy is traced in connection with the “Duchan” (properly the platform — the place on which the Levites were stationed for the service of song in the Temple), as it is said, (I Chronicles 6:22—23) “the son of Ebiasaph, the son of Korah, the son of Izhar, the son of Kohath, the son of Levi, the son of Israel” (Midrash Tanchuma, Korach 4).
Da'at Zekenim
בן לוי, “the son of Levi;” “who made himself a companion to gehinom, hell.” You may ask why the Torah does not also trace him to the founding father of the Jewish nation, to Yaakov? This is answered by a Rabbi Shmuel son of Yitzchok, who says that Yaakov prayed that his name not be associated with such a person as Korach. This is how he understood Genesis 49,6: בקהלם אל תחד כבודי, “let my honour not be associated with their counsel.”
Siftei Chakhamim
Where is his name mentioned. Meaning: where is the name of Yaakov mentioned in connection with Korach such that one has to explain why his name is not mentioned here; for surely it is usual for genealogy to be traced back only to the tribe. Re’m writes that there is still a difficulty according to the Midrash (Tanchuma 3) which expounds the verse (Bereishis 49:6) “Do not let my soul come into their plot” as referring to the incident of the spies. Similarly there is a difficulty according to Rashi’s explanation in Parshas Vayechi that “Do not let my soul come into their plot” refers to the incident with Zimri ben Salu, leader of paternal house of Shimon (Bamidbar 25:14). There Rashi did not ask where else the name “son of Yaakov” was mentioned concerning Zimri such that one would have to explain why it was not mentioned. Re’m leaves the matter as requiring further investigation. See what I wrote in Parshas Vayechi that answers the question of Re’m.
Rashi
מה אקב ולא קבה אל HOW SHALL I CURSE WHOM GOD HATH NOT CURSED — Even when they deserved to be cursed, they were not cursed. When their ancestor, Jacob, made mention of their sin — (Genesis 49:6) “For in their anger they slew a man” — he cursed their anger only, as it is said, (Genesis 49:7) “Cursed be their anger”. When their ancestor, Jacob, went to his father with deceit he deserved to be cursed, but what is stated there (Genesis 27:33)? “Yea, he shall be blessed”. In the case of those tribes who had to recite the blessings it is said, (Deuteronomy 27:12) “These shall stand to bless the people”, but in the case of those who had to pronounce the curses it does not state, “And these shall stand to curse the people”, but, “And these shall stand for the curse”, — it does not wish to mention the term “cursing” in direct reference to them (the people) (Midrash Tanchuma, Vayechi 1; Midrash Tanchuma, Balak 12).