21 “You have heard that it was said to the people long ago, ‘You shall not murder,[a] and anyone who murders will be subject to judgment.’ 22 But I tell you that
anyone who is angry with a brother or sister[b][c] will be subject to judgment. Again, anyone who says to a brother or sister, ‘Raca,’[d] is answerable to the court. And anyone who says, ‘You fool!’ will be in danger of the fire of hell.
Jesus is addressing the heart of an individual. The heart is the extreme focus of Jesus. He spends the better part of the Sermon on the Mount addressing this. Jesus knew that avoiding murder is largely a physical issue but avoiding anger is a spiritual one.
Jesus always emphasizes the spiritual over the physical. I may never reach a point of wanting to murder someone but that doesn’t mean that anger doesn’t have a hold on me. That doesn’t mean that the contempt I have for another person isn’t tearing myself and that person apart. Dallas Willard says, “Anything that can be done with anger can be done better without it.”
There are some Christians that think that it is their Christian duty to be angry people against those that are hostile towards them. Nothing could be further from the truth. Encountering those who are against us in a loving and respectful way instead of a belligerent and rageful way is to follow the example of Jesus. To do otherwise is to follow the ways of the world and to work against Jesus’ teaching on the destructiveness of anger.