Chapter 28 — Part III: The Decalogue — The Fifth Commandment
Section 17. Sinful Anger Is Also Forbidden By The Fifth Commandment — The Jews, with singular dullness of apprehension, thought that to abstain from taking life with their own hands was enough to satisfy the obligation imposed by this Commandment. But the Christian, instructed in the interpretation of Christ, has learned that the precept is spiritual, and that it commands us not only to keep our hands unstained, but our hearts pure and undefiled; hence what the Jews regarded as quite sufficient, is not sufficient at all. For the Gospel has taught that it is unlawful even to be angry with anyone: But I say to you that whosoever is angry with his brother, shall be in danger of the judgment. And whosoever shall say to his brother, "Raca," shall be in danger of the council. And whosoever shall say, "Thou fool," shall be in danger of hell fire. From these words it clearly follows that he who is angry with his brother is not free from sin, even though he conceals his resentment; that he who gives indication of his wrath sins grievously; and that he who does not hesitate to treat another with harshness, and to utter contumelious reproaches against him, sins still more grievously.