“You have heard that it was said to those of old, ‘You shall not murder, and whoever murders will be in danger of the judgment.’ But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, ‘Raca!’ shall be in danger of the council. But whoever says, ‘You fool!’ shall be in danger of hell fire.”
In His Sermon on the Mount, Jesus Christ expanded on and magnified the laws of the Holy Scriptures to show more clearly their spiritual intent.
In this passage in Matthew 5:21-22 He shows that there’s more to the Sixth Commandment than just not murdering another person. The attitude of murder starts in our hearts and our minds and is reflected in our words and actions. Selfish anger and hateful words can break the spirit of the law against murder.
For more about the spiritual intent of the law against murder, see “Fighting the Works of the Flesh: Hatred.”