The passuk states ויקח קרח… and Korach took… and Dasan and Avirom, Eliav’s sons, and Ohn Ben Peles, Reuven’s sons. What did Korach take?
Rashi explains Korach convinced two hundred and fifty heads of Sanhedrin with words to join him. Then he dressed them in tallisos which were completely techeiles. They stood before Moshe and asked him, “Is a tallis which is completely techeiles obligated in having tzitizis of techeiles? Moshe answered, “It is obligated.” They started making fun of him saying, “If one string of techeiles will be sufficient for the tallis of another type of material, this tallis which is completely techeiles should certainly be able to exempt itself. So too, the entire assembly is holy, they all heard the dibros from Hashem on Har Sinai. Just as a tallis of techeiles shouldn’t need another string of techeiles, so too we don’t need you as our leaders, we can lead ourselves.”
The Maharal explains Rashi that Korach took the two hundred and fifty people by convincing them with words, which in essence is taking the person himself.
Onkelos explains differently, that Korach separated himself. Rashi explains this reflects that Korach separated himself from the gathering to strengthen the argument and arouse questions about Kehuna. This explanation is hinted in the passuk as it does not mention what or whom Korach took, other than himself. Korach took himself away from everyone to separate from them. The Ramban explains Onkelos differently, Korach took himself with thought, in order to know what to say and do. The Maharal explains Rashi also understands this way. Korach did not actually move to another side. Rather, Korach took himself with thought, thereby separating himself away from everyone else.
Further on in the Parsha it states that there were fourteen thousand and seven hundred who died, besides for those who died “על דבר קרח” which Onkelos translates as “for the argument of Korach.” This shows that Hashem punished Korach and his followers for arguing against Moshe. So too the Mishnah brings Korach and his followers as an example of an argument not l’Shem Shamayim.
My Rosh Hayeshiva HaRav Yaakov Friedman shlita said, “Often when a person has a conflict with another and gets upset, it is common for him to think about what happened, review the experience, and remind himself exactly what took place. One pictures the exact action of the other person which caused the hatred, the expression on the face, the words which were said, and the tone of voice in which it was said. This causes the argument to flare up, from a burnt out coal into a blazing fire. By doing this one falls into the clutches of Korach and his followers. Instead, one should focus on the good of the other person, and remind oneself about the nice things he has done.
May we stay away from arguments and be vigilant about not behaving like Korach and his followers.