THE CAPITAL SINS 73 



though covetousness is in itself but a venial sin, "yet it is 

 very dangerous because of man's proneness to it, and 

 because the vice is apt to grow fast by what it feeds upon, 

 until it becomes mortally sinful. Holy Scripture fre- 

 quently condemns it and warns us against it." 18 



III. Lust. — Lust (luxuria) 19 is an inordi- 

 nate desire for the pleasure which has its seat in 

 the organs of generation. Sins of lust may be 

 internal (thoughts and desires) or external 

 (words and acts). In these sins there is no 

 smallness of matter (parvitas materiae), but 

 every act of wrongful indulgence in venereal 

 pleasure, if directly sought or consented to, is 

 grievously sinful. No sin against chastity is 

 venial except that which remains internally 

 incomplete (actus imperfectus), not on account 

 of outward circumstances, but because the will 

 resists. 



Not all sins against the Sixth and Ninth Command- 

 ments, therefore, are mortal. If an impure thought, 

 word, or act is freely willed, or, a fortiori, if it is delib- 

 erately excited, it is a mortal sin. Not so if it arises 

 in the mind against one's will or without one's deliberate 

 consent. External acts, such as immodest touches, looks, 

 etc., are mortally sinful if due to lust; they are venially 

 sinful if due to curiosity or inadvertence, and transient 



18 Th. Slater, S.J., A Manual of ma Theologica, 2a 2ae, qu. 153 sq.: 

 Moral Theology, Vol. I, pp. 157 sq. St. Alphonsus, Theol. M oralis, 1. 

 — Cfr. 1 Tim. VI, 9, etc. Ill, n. 412 sqq. (ed. Gaude, Vol. I, 



19 Cfr. St. Thomas Aquinas, Sum- pp. 665 sqq.). 



