LEV574 The biblical law [this verse] implies that not all anger should be repressed. The Bible does not forbid all hatred, but only that which you are keeping secret. Therefore it is best to tell the person who has offended you why you are angry, because doing so might lead to a change in the person's behavior or to an apology--and to reconciliation. Rashi, commenting on Numbers 12:9, suggests that you should not become angry at someone without first telling the person what he is doing that has upset you. Once you have done this (and your reason is valid), then, if the person does not alter his behavior, you have the right to be angry at him.