Musar sur Les Nombres 17:5

“And not be like Korach and like his community” (Numbers 17:5). And our Rabbis, may their memory be blessed, said (Sanhedrin 110a), “Anyone who perpetuates a dispute violates a negative commandment, as it is stated ‘and not be like Korach and like his community.’” But it is permissible to say evil speech about disputatious people, as it is stated (I Kings 1:26), “But he did not invite me your servant, or the priest Zadok, etc.”

One must also take care not to be among the abettors of machloketh so that he not be punished among them when their appointed time comes, as Chazal have stated (Makkoth 5b): "Scripture has punished the abettors of transgressors as the transgressors themselves." And in Midrash Parshath Korach we find: "Come and see how severe is machloketh. For if one abets machloketh, the Holy One Blessed be He destroys his remembrance, as it is written (Numbers 16:35): 'And a fire went forth from the L-rd and consumed the hundred and fifty men, the presenters of the incense.'" And, in Sanhedrin 110a: "Rav said: 'All who persist in machloketh transgress a negative commandment, viz. (Numbers 17:5): "And he shall not be like Korach and like his congregation."' R. Assi said: 'He deserves to contract tzara'ath.'" (And see above, Chapter VI, what is written in the name of Sefer Hakaneh, that sometimes the Holy One Blessed be He transforms the punishment of tzara'ath to poverty, so that he becomes dependent upon others.)