527. What is required by the ninth commandment?The ninth commandment requires that one overcome carnal concupiscence in thought and in desire. The struggle against such concupiscence entails purifying the heart and practicing the virtue of temperance.
Further reading: CCC 2514-2516528. What is forbidden by the ninth commandment?
The ninth commandment forbids cultivating thoughts and desires connected to actions forbidden by the sixth commandment.
Further reading: CCC 2517-2519, 2531-2532