QUESTION 56: OF THE PRECEPTS RELATING TO PRUDENCE
We must now consider the precepts relating to prudence, under which head
there are two points of inquiry:
(1) The precepts of prudence;
(2) The precepts relating to the opposite vices.
Article 1: Whether the precepts of the decalogue should have included a precept of prudence?
Objection 1: It would seem that the precepts of the decalogue should have
included a precept of prudence. For the chief precepts should include a
precept of the chief virtue. Now the chief precepts are those of the
decalogue. Since then prudence is the chief of the moral virtues, it
seems that the precepts of the decalogue should have included a precept
Objection 2: Further, the teaching of the Gospel contains the Law especially
with regard to the precepts of the decalogue. Now the teaching of the
Gospel contains a precept of prudence (Mt. 10:16): "Be ye . . . prudent
[Douay: 'wise'] as serpents." Therefore the precepts of the decalogue
should have included a precept of prudence.
Objection 3: Further, the other lessons of the Old Testament are directed to
the precepts of the decalogue: wherefore it is written (Malach. 4:4):
"Remember the law of Moses My servant, which I commanded him in Horeb."
Now the other lessons of the Old Testament include precepts of prudence;
for instance (Prov. 3:5): "Lean not upon thy own prudence"; and further
on (Prov. 4:25): "Let thine eyelids go before thy steps." Therefore the
Law also should have contained a precept of prudence, especially among
the precepts of the decalogue.
The contrary however appears to anyone who goes through the precepts of
I answer that, As stated above (FS, Question , Article ; Article , ad 1) when we
were treating of precepts, the commandments of the decalogue being given
to the whole people, are a matter of common knowledge to all, as coming
under the purview of natural reason. Now foremost among the things
dictated by natural reason are the ends of human life, which are to the
practical order what naturally known principles are to the speculative
order, as shown above (Question , Article ). Now prudence is not about the end,
but about the means, as stated above (Question , Article ). Hence it was not
fitting that the precepts of the decalogue should include a precept
relating directly to prudence. And yet all the precepts of the decalogue
are related to prudence, in so far as it directs all virtuous acts.
Reply to Objection 1: Although prudence is simply foremost among all the moral
virtues, yet justice, more than any other virtue, regards its object
under the aspect of something due, which is a necessary condition for a
precept, as stated above (Question , Article ; FS, Question , Articles ,5). Hence it
behooved the chief precepts of the Law, which are those of the decalogue,
to refer to justice rather than to prudence.
Reply to Objection 2: The teaching of the Gospel is the doctrine of perfection.
Therefore it needed to instruct man perfectly in all matters relating to
right conduct, whether ends or means: wherefore it behooved the Gospel
teaching to contain precepts also of prudence.
Reply to Objection 3: Just as the rest of the teaching of the Old Testament is
directed to the precepts of the decalogue as its end, so it behooved man
to be instructed by the subsequent lessons of the Old Testament about the
act of prudence which is directed to the means.
Article 2: Whether the prohibitive precepts relating to the vices opposed to prudence are fittingly propounded in the Old Law?
Objection 1: It would seem that the prohibitive precepts relating to the
vices opposed to prudence are unfittingly propounded in the Old Law. For
such vices as imprudence and its parts which are directly opposed to
prudence are not less opposed thereto, than those which bear a certain
resemblance to prudence, such as craftiness and vices connected with it.
Now the latter vices are forbidden in the Law: for it is written (Lev.
19:13): "Thou shalt not calumniate thy neighbor," and (Dt. 25:13): "Thou
shalt not have divers weights in thy bag, a greater and a less."
Therefore there should have also been prohibitive precepts about the
vices directly opposed to prudence.
Objection 2: Further, there is room for fraud in other things than in buying
and selling. Therefore the Law unfittingly forbade fraud solely in buying
Objection 3: Further, there is the same reason for prescribing an act of
virtue as for prohibiting the act of a contrary vice. But acts of
prudence are not prescribed in the Law. Therefore neither should any
contrary vices have been forbidden in the Law.
The contrary, however, appears from the precepts of the Law which are
quoted in the first objection.
I answer that, As stated above (Article ), justice, above all, regards the
aspect of something due, which is a necessary condition for a precept,
because justice tends to render that which is due to another, as we shall
state further on (Question , Article ). Now craftiness, as to its execution, is
committed chiefly in matters of justice, as stated above (Question , Article ):
and so it was fitting that the Law should contain precepts forbidding the
execution of craftiness, in so far as this pertains to injustice, as when
a man uses guile and fraud in calumniating another or in stealing his
Reply to Objection 1: Those vices that are manifestly opposed to prudence, do not
pertain to injustice in the same way as the execution of craftiness, and
so they are not forbidden in the Law, as fraud and guile are, which
latter pertain to injustice
Reply to Objection 2: All guile and fraud committed in matters of injustice, can
be understood to be forbidden in the prohibition of calumny (Lev. 19:13).
Yet fraud and guile are wont to be practiced chiefly in buying and
selling, according to Ecclus. 26:28, "A huckster shall not be justified
from the sins of the lips": and it is for this reason that the Law
contained a special precept forbidding fraudulent buying and selling.
Reply to Objection 3: All the precepts of the Law that relate to acts of justice
pertain to the execution of prudence, even as the precepts prohibitive of
stealing, calumny and fraudulent selling pertain to the execution of