Rather, the attitude of our hearts determines whether or not we are right with God. To obey a rule, while in our heart we harbor anger, deceit, unfaithfulness, hypocrisy, revenge or resentment, is in reality to sin against God. Jesus begins with the sixth commandment, You shall not murder. Murder is not accidental death. It is a deliberate act of taking the life of another human being.
Murder is a response to some other human emotion, especially anger.
When a person gets angry with someone, evil thoughts towards that person fill their mind. The act of murder is then a reaction to the attitude that already exists in their heart. When we allow anger to fill our minds, we open ourselves up to actions that can cause us to sin, to break the commands of God. Not getting our way. Not getting the money or recognition or respect that we think we deserve.