But I say to you: whoever becomes angry with his brother without cause will be subject to judgment, and whoever says to his brother, ‘Fool,’ will be subject to the council, and whoever says to his brother, ‘You moron,’ will be condemned to the fire of Gehenna.
Here Jesus deepens the meaning of the commandment “Do not murder,” revealing that sin begins not with the act, but with the condition of the heart. Not only murder is condemnable, but also unjust anger and contempt toward a brother (and toward any person), because these feelings break the law of love and peace. The words “fool” and “moros” point to an insult born of pride, which before God is as serious as a violent deed. This saying teaches that true righteousness is measured not by outward conduct, but by purity of heart and by one’s attitude toward one’s neighbor.