Like being zapped by a bolt of lightning, the religious leaders of Jesus' day were shocked by what He was teaching His disciples in the Sermon on the Mount. Not only did these Pharisees try to obey all the Law but they had invented rules about the rules. See how Jesus ignored their human righteousness and taught that it's possible to commit murder in our hearts by having unjust anger at people and calling them insulting names. Understand that he was pointing out to them that only He could fulfill the Law and live a perfect life. Accept the importance of believers' settling grievances with others quickly instead of letting them fester so our prayers will be answered.