Catechism of the Catholic Church §1962 — excerpt
The Old Law is the first stage of revealed Law. Its moral prescriptions are summed up in the Ten Commandments. the precepts of the Decalogue lay the foundations for the vocation of man fashioned in the image of God; they prohibit what is contrary to…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Augustine, En. in Ps. 57, 1: PL 36, 673