Parshat Bamidbar, among many other things, subtly contrasts the effects of a good neighbor vs a bad one. In describing the camp arrangements, the Kehat family (Korach and his gang) camped “southward” (3:29), as did Reuven (2:10), to which Rash comments that “woe to an evil person, woe to his neighbors.” Similarly, Yehuda, YIssachar and Zevulun got to live next door to Moshe and Aaron (3:39) and benefited, to which Rashi points out that “happy is a righteous person, happy is his neighbor.” As Elisha Greenbaum points out (Chabad.org), however, there is a difference between the two…

With Moses and Aaron living nearby, three entire tribes benefited and their positive influence lasted throughout history. Contrast this with the pernicious effect of living next to Korach; only a tiny fraction of the one tribe living closest was negatively influenced. Even when the negative influence is right next door, you have the ability to resist their blandishments by connecting to G‑d and his Torah. You’ll also notice that both of Rashi’s comments focus on the person, and our effect on our neighbors. We have the power to affect our neighbors positively or negatively, so long as we resist the negative influences around us, and choose to be propelled by the positive ones.