“The Talmud says that Shalom is one of the names of the Almighty [Shabbos 10b]. …This too is the reason we may invoke the Name of G-d to say hello to someone. When Jews are at peace with one another, the Shechinah dwells amongst us. When we are not living in peace, the Almighty removes His Presence from amongst us. It is worthwhile to use the Name of G-d to greet someone and be friendly, thereby promoting unity amongst the Jewish people.
Jewish unity causes the Divine Presence to be present amongst us. …unity was the key to survival of the Jewish people — it is their only hope for survival. He knew that the Divine Presence would only reside with the nation through ‘achdus’. Consequently, Yaakov wanted to have nothing to do with Korach and his disputants. In Yaakov’s eyes, their aveyro was worse than that of the Golden Calf and the Spies and the Complainers, and everything else. This aveyro resulted in sowing division and dispute amongst the Jewish people. Korach threatened to destroy all that Yaakov had built. About such an aveyro, Yaakov pleaded, ‘Let my name and honor not be associated with him.’ Only through unity will the Children of Yaakov be the eternal nation of Bnei Yisrael.”