The Shlah (Korach, Derech Chaim Tochachas Mussar, 26) writes, "From the story of Korach's dispute, we learn mussar to avoid machlokes. Think about the severe punishment that came to Korach... Dasan and Aviram also died, together with their infants, although the court in heaven doesn't punish people below twenty (Shabbos 89:). But this time, even children perished. Such is the severity of machlokes (Tanchuma, Korach 3). Let us learn from this always to embrace peace."
The Rambam (in a letter) writes, "Don't contaminate your souls with machlokes that destroy the body, neshamah, and wealth. I saw families perish, cities destroyed, communities dispersed, chassidim lost, honored people disgraced, all due to machlokes. The nevi'im told prophecies, and scholars spoke wisdom regarding the severity of machlokes, but even they haven't fully described just how bad it is. Therefore, hate it, run away from it, and keep away from all those who love machlokes, lest you be punished with them."
Reb Chaim Palagi zt'l writes, "I have seen several instances where any man or woman, family, country, or city involved in a machlokes, both sides didn’t come out clean. They were smitten on their bodies, and with their money, rachmanah litzlan. Someone
