Treatise I: On the Precepts of the Church

What precepts of the Church come to be considered. As many as have been prescribed by general laws of the Code or by particular laws, indeed or by use of jurisdiction, so many in truth are precepts of the Church. By this reason, in every part of moral theology there is speech about the precepts of the Church, and there are also many precepts which are necessarily passed over in moral books. Nevertheless, by a more restricted use of the word, by the name precepts of the Church there have customarily been called a few prescriptions, of very general use, which in catechism formulas are proposed to the faithful to be held by memory. These are now to be explained by us. To these, however, the laws concerning the censure and prohibition of books must be joined.

Moreover, these common precepts can conveniently be referred to the Christian virtues. For the precepts concerning annual confession and Paschal communion are connected with the general pursuit of justice and sanctity; the canons concerning the censure and prohibition of books are directed chiefly to protecting the virtue of faith; the obligation of sanctifying feasts coheres with the virtue of religion; but by the precept concerning fast and abstinence the virtue of temperance to be exercised is inculcated. The precepts concerning annual confession and communion, however, were proposed in the treatises on the Eucharist and Penance.