The Mishnah contrasts machlokes l”sheim shamayim, a dispute for the sake of Heaven, with one that is not. The former is epitomized by the disputes of Hillel and Shammai whose differing views in matters of halachah are reverently studied and pondered generation after generation as eternal components of the Oral Law. The latter is epitomized by the dispute of Korach, whose personal feud against Moshe Rabbeinu earned him an untimely death and eternal dishonor. As the Chofetz Chaim notes in his preface to Sefer Chofetz Chaim, one whose sinful talk fuels strife transgresses the prohibition, “that he not be like Korach and his assembly”.
To the Jew, intellectual disagreement in a common search for truth is an integral part of life. As a spiritual, thinking people, Jews are forever involved in discussion of ideas.
Conversely, personal bickering, jealousy, and competition are signs of immaturity and weakness. They have no place in the world of the Jew.
The difficulty, however, lies in our tendency to transform every dispute into an ideological one. Korach, too, came with a philosophy: that all Jews are equally holy, and thus there is no justification for one family, Aharon and his Kohanim descendants, to be above everyone else.
The Sages teach that Korach’s argument as rooted in jealousy, resulting from his having been passed over for the position of prince of his Levite family.
Before embarking on an ideological campaign against others, one must ask himself: “Am I honestly promoting the cause of truth, or am I involved in a personal feud disguised as an ideological debate?”
Ideological disagreement should never lead to personal animosity. When Torah scholars disagree, their dispute is over ideals, and is never personal. When a scholar is involved in a dispute, his followers must be careful not to become involved in a matter that is not their own, and certainly should avoid character assassination and personal hatred towards his opponent.
Sefer Chofetz Chaim, 18 Kislev, page 204 and 408