ולא תונו איש את עמיתו
The Sefer Yereim contends that just as there is an admonition against onaas devarim, hurting a person with words, saying something to him that disconcerts and makes him feel bad, there is also an enjoinment against looking at someone with a bad/evil look. The way we look at someone – be it with disdain, scorn, or hatred – can and does hurt. Onaas mamone is the prohibition against cheating someone financially. It is a surreptitious form of stealing. In truth, one only fools himself. Horav Menachem Mendel, z.l., m’Varko, said, “According to Halachah, one should not cheat another Jew. Lifnim meshuras…