Article V. On the Vice Opposed to Chastity, Namely, Lust

680. Preliminary note. There are two kinds of crimes which draw many men into hell: the concupiscence of the flesh and the covetousness of riches. Each of these crimes is forbidden by a twofold precept: the concupiscence of the flesh by the sixth and ninth; but the covetousness of things by the seventh and tenth precepts; while a vice of every other kind is prohibited by only one precept. Yet it is not lawful to deduce from this that the sins of lust and avarice are graver than all the others; for it is certain that some sins, for example, blasphemy, perjury, hatred, etc., are graver than they. Nevertheless, because men are more vehemently carried away by passion into these two vices, God therefore willed to deter men from this ruin by a twofold express precept. - The matter of the sixth and ninth precepts is extensive, filthy, and pestilential, raging to the destruction of bodies no less than of souls; it is more difficult to explain, not because it is difficult to show its repugnance to reason and the divine law, but because it is so sticky, so unspeakable, that discourse about it can scarcely be had without the tongue, mind, and ears being defiled. Therefore the Catechism of the Council of Trent wisely admonishes:¹³¹⁷ "In explaining this very matter, let the pastor be exceedingly cautious and prudent, and let him recall in veiled words the matter which demands moderation rather than copiousness of speech. For it is to be feared lest, while he endeavors to explain at length and too copiously the ways in which men depart from the prescription of this law, he may perhaps fall into discussion of those things from which matter for exciting lust rather than a means of restraining it is wont to issue." Would that several casuists, who rolled this pitch with their pen more than was just, had taken this most salutary admonition more to heart. The modesty implanted by nature condemns, execrates, and shudders at a great part of those questions which in certain authors are discussed broadly to the nausea of readers. A minute knowledge of all these things is not necessary for a confessor, because several foul circumstances added to lewd acts do not notably change the morality of the act. Some clear principles and certain practical rules plainly suffice for resolving all cases. Hence we endeavor to set forth briefly and clearly those things which are necessary to know concerning this filthy matter, inviting the reader to pray with us: Burn with the fire of the Holy Spirit our reins and our heart, O Lord, that we may serve Thee with a chaste body and please Thee with a clean heart, through Christ and the Blessed Virgin. Amen. - We divide the whole tract on lust into five sections: 1. on lust in general; 2. on internal sins; 3. on external non-consummated sins; 4. on external sins consummated according to nature; 5. on external sins consummated contrary to nature.

¹³¹⁷ Part III, c. 7, q. 1.