Treatise — Marc, Institutiones Morales
TREATISE VI: On the Sixth and Ninth Precept of the Decalogue
You shall not commit adultery.....
You shall not desire his wife (of your neighbor).
(Exod., 20, 14, 17).
Admonition of St. Alphonsus. "Now we undertake with difficulty to treat that matter whose name alone infects the minds of men.... Would that I could have explained myself more briefly or more obscurely! But since this is the more frequent and abundant matter of confessions, and because of it a greater number of souls slide down to hell; indeed I do not hesitate to assert, on account of this one vice of impurity, or at least not without it, all are damned whoever are damned: hence it was necessary for me, for the instruction of those who desire to learn moral science, to explain myself clearly (though as chastely as could be done), and to discuss very many particulars. - Yet I pray students, ... that they not read this treatise on the sixth precept (as also that other one on the conjugal debt), unless they are now close to hearing confessions; and that they read for this sole end, casting aside absolutely all curiosity, and at that time more often lift the mind to God, and commend themselves to the Immaculate Virgin, lest, while they strive to acquire others' souls for God, they themselves suffer detriment of their own" (III, 413).
- The sixth precept is joined by a close affinity to the fifth; for since the fifth precept looks chiefly to this, that human life, when it already exists in the nature of things, be rightly cared for, the principal scope of the sixth precept is that watchfulness be exercised over its very beginnings, and that human nature be conserved: for divine sanction ought to protect not only life, but also that wonderful faculty which man possesses, of communicating life. Cf. Pruner, Spez. Moraltheol., IV Absch., II Tr.
By this precept only adultery, which at once injures justice and chastity, is explicitly forbidden; but implicitly all things whatever that are dishonorable and immodest are forbidden, and it is prescribed that we cultivate chastity of mind and body (Roman Catechism, P. III, c. 7, n. 2).
The ninth precept, which is most closely joined to the sixth, prohibits in the same matter sins of the heart, or wicked thoughts and desires. Of these we have already treated in the treatise on Sins, n. 345 ff.
Hence, in the present treatise, we shall treat: 1. of chastity and lust in general; - 2. of sins of consummated lust; - 3. of sins of non-consummated lust (which are postponed here, because they derive their species from the preceding); - 4. of dangers to chastity.