How Does Hate Diminish You?

A person can't be a truly frum Jew if he hates another frum Jew. Such a person inevitably starts looking for faults in his fellow Jews. That leads to thinking that frum Jews are no good in general, resulting in the seeds of apikorsus (heresy) being planted in his mind... A person who  harbors ill-will towards people who serve Hashem should know that he himself is not really a frum Jew. -- Ohr Avigdor Hakdama