Thomas Aquinas

“ Certain persons refrain from lustful pleasures chiefly through hope of the glory to come, which hope is removed by despair, so that the latter is a cause of lust, as removing an obstacle thereto, not as its direct cause; whereas this is seemingly necessary for a capital vice. ”

“ A thing may be a hindrance to virtue in two ways. First, as regards the ordinary degree of virtue, and as to this nothing but sin is an obstacle to virtue. Secondly, as regards the perfect degree of virtue, and as to this virtue may be hindered by that which is not a sin, but a lesser good. In this way sexual intercourse casts down the mind not from virtue, but from the height, i.e. the perfection of virtue. ”

“ Although wanton pleasure applies to other matters, the name of lust has a special application to venereal pleasures, to which also wantonness is specially applicable, as Augustine remarks (De Civ. xiv, 15,16) .
Art. 1 - Whether no venereal act can be without sin? Objection 1: It would seem that no venereal act can be without sin. For nothing but sin would seem to hinder virtue. Now every venereal act is a great hindrance to virtue. ”

“ Further, everyone can lawfully make what use he pleases of what is his. But in the venereal act a man uses only what is his own, except perhaps in adultery or rape. Therefore there can be no sin in venereal acts, and consequently lust is no sin. ”

“ Even as temperance chiefly and properly applies to pleasures of touch, yet consequently and by a kind of likeness is referred to other matters, so too, lust applies chiefly to venereal pleasures, which more than anything else work the greatest havoc in a man's mind, yet secondarily it applies to any other matters pertaining to excess. ”

“ The opposite of lust is not found in many, since men are more inclined to pleasure. Yet the contrary vice is comprised under insensibility, and occurs in one who has such a dislike for sexual intercourse as not to pay the marriage debt
Art. 3 - Whether lust is a capital vice? Objection 1: It seems that lust is not a capital vice. For lust is apparently the same as "uncleanness," according to a gloss on Eph. ”

“ The fourth act is the reason's command about the thing to be done, and this also is impeded by lust, in so far as through being carried away by concupiscence, a man is hindered from doing what his reason ordered to be done. ”

“ Fourthly, on account of the sentiments expressed by his words, for through causing blindness of mind, lust perverts a man's sentiments, and so he gives way "to foolish talking," for instance, by expressing a preference for the pleasures he desires to anything else. ”

“ Secondly, on account of the cause: for, since lust causes thoughtlessness and rashness, the result is that it makes a man speak without weighing or giving a thought to his words. which are described as "scurrilous." Thirdly, on account of the end: for since the lustful man seeks pleasure, he directs his speech thereto, and so gives utterance to "wanton words." ”

“ For it is said to be superfluous, because it is the residue from the action of the nutritive power, yet it is needed for the work of the generative power. But the other superfluities of the human body are such as not to be needed, so that it matters not how they are emitted, provided one observe the decencies of social life. ”