GEN1117 If you hate someone, you should tell the person why you hate him or her and what this person has done wrong, says Maimonides.   Book of Commandments, negative Mitzvah 302.   Sefer HaChinuch, Mitzvah 338 continues this theme and also says that openly stating one’s hate removes any violation of the sin of hatred, which must take place only in one’s heart to be a Torah violation.  However, by announcing his hate, the person does violate the prohibition of taking revenge and does not fulfill the Mitzvah-commandment of “loving one’s fellow neighbor as oneself.” That is why Abraham openly admonished King Avimelech when his servants had stolen from Abraham.   According to tradition, Abraham observed the entire Torah, so he knew that the prohibition of hatred was to keep that antipathy within his heart.   Thus, he told Avimelech about his feelings and explained why he felt that way.   AMJV 129