sin attaching to the emission of other
superfluities. Therefore neither can there be any sin in venereal
acts.

Obj. 2: 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.

Obj. 3: Further, every sin has an opposite vice. But, seemingly, no
vice is opposed to lust. Therefore lust is not a sin.

_On the contrary,_ The cause is more powerful than its effect. Now
wine is forbidden on account of lust, according to the saying of the
Apostle (Eph. 5:18), "Be not drunk with wine wherein is lust [Douay:
'luxury']." Therefore lust is forbidden.

Further, it is numbered among the works of the flesh: Gal. 5:19
[Douay: 'luxury'].

_I answer that,_ The more necessary a thing is, the more it behooves
one to observe the order of reason in its regard; wherefore the more
sinful it becomes if the order of reason be forsaken. Now the use of
venereal acts, as stated in the foregoing Article, is most necessary
for the common good, namely the preservation of the human race.
Wherefore there is the greatest necessity for observing the order of
reason in this matter: so that if anything be done in this connection
against the dictate of reason's ordering, it will be a sin. Now lust
consists essentially in exceeding the order and mode of reason in the
matter of venereal acts. Wherefore without any doubt lust is a sin.

Reply Obj. 1: As the Philosopher says in the same book (De Gener.
Anim. i, 18), "the semen is a surplus that is needed." 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. It is different with the
emission of semen, which should be accomplished in a manner befitting
the end for which it is needed.

Reply Obj. 2: As the Apostle says (1 Cor. 6:20) in speaking against
lust, "You are bought with a great price: glorify and bear God in
your body." Wherefore by inordinately using the body through lust a
man wrongs God Who is the Supreme Lord of our body. Hence Augustine
says (De Decem. Chord. 10 [*Serm. ix (xcvi de Temp.)]): "God Who thus
governs His servants for thei