Chapter — Vermeersch, Theologia Moralis
Title I: On the Precept of the Sanctification of Feasts
Utility. - I. Concerning positive sanctification. The apostolic man must first of all endeavor to persuade not a merely literal observation of the precept, but also the true religious intention of these prescriptions. For solving cases it will be especially useful to him to have distinct concepts concerning the necessity of assistance and of presence at Mass, and to discern well the causes of excuse. Yet he will admit these in such a way that at the same time he is solicitous for fostering religious learning and practice in those who are often compelled to be absent from sacred offices.
II. As to negative sanctification, an accurate, filial, non-Judaic manner of abstaining from servile works must be obtained from Christians. For himself the priest will have to form a criterion for estimating what things are certainly licit or not licit, and what are legitimate excuses.