A full explanation of the commandments of the Decalogue became necessary in the state of sin because the light of reason was obscured and the will had gone astray. 32
Catechism number 2073
Obedience to the Commandments also implies obligations in matter which is, in itself, light. Thus
abusive language is forbidden by the fifth commandment, but would be a grave offense only as a result of
circumstances or the offender's intention. "Apart from me you can do nothing"