Whether He Sins Who Demands an Oath of a Perjurer?
Objection 1: It would seem that he who demands an oath of a perjurer
commits a sin. Either he knows that he swears truly, or he knows that
he swears falsely. If he knows him to swear truly, it is useless for
him to demand an oath: and if he believes him to swear falsely, for
his own part he leads him into sin. Therefore nowise seemingly should
one enjoin an oath on another person.
Obj. 2: Further, to receive an oath from a person is less than to
impose an oath on him. Now it would seem unlawful to receive an oath
from a person, especially if he swear falsely, because he would then
seem to consent in his sin. Much less therefore would it seem lawful
to impose an oath on one who swears falsely.
Obj. 3: Further, it is written (Lev. 5:1): "If anyone sin, and hear
the voice of one swearing falsely [*'Falsely' is not in the Vulgate],
and is a witness either because he himself hath seen, or is privy to
it: if he do not utter it, he shall bear his iniquity." Hence it
would seem that when a man knows another to be swearing falsely, he
is bound to denounce him. Therefore it is not lawful to demand an
oath of such a man.
Obj. 4: On the other hand, Just as it is a sin to swear falsely so is
it to swear by false gods. Yet it is lawful to take advantage of an
oath of one who has sworn by false gods, as Augustine says (ad
Public. Ep. xlvii). Therefore it is lawful to demand an oath from one
who swears falsely.
_I answer that,_ As regards a person who demands an oath from
another, a distinction would seem to be necessary. For either he
demands the oath on his own account and of his own accord, or he
demands it on account of the exigencies of a duty imposed on him. If
a man demands an oath on his own account as a private individual, we
must make a distinction, as does Augustine (de Perjuriis. serm.
clxxx): "For if he knows not that the man will swear falsely, and
says to him accordingly: 'Swear to me' in order that he may be
credited, there is no sin: yet it is a human temptation" (because, to
wit, it proceeds from his weakness in doubting whether the man will
speak the truth). "This is the evil whereof Our Lord says (Matt.
5:37): That which is over and above these, is of evil. But if he
knows the man to have done so," i.e. the contrary of what he swears
to, "and yet forces him to swear, he is a murderer: for the other
destroys himself by his perjury, but it is he who urged the hand of
the slayer."
If, on the other hand, a man demands an oath as a public person, in
accordance with the requirements of the law, on the requisition of a
third person: he does not seem to be at fault, if he demands an oath
of a person, whether he knows that he will swear falsely or truly,
because seemingly it is not he that exacts the oath but the person at
whose instance he demands it.
Reply Obj. 1: This argument avails in the case of one who demands an
oath on his own account. Yet he does not always know that the other
will swear truly or falsely, for at times he has doubts about the
fact, and believes he will swear truly. In such a case he exacts an
oath in order that he may be more certain.
Reply Obj. 2: As Augustine says (ad Public. serm. xlvii), "though we
are forbidden to swear, I do not remember ever to have read in the
Holy Scriptures that we must not accept oaths from others." Hence he
that accepts an oath does not sin, except perchance when of his own
accord he forces another to swear, knowing that he will swear falsely.
Reply Obj. 3: As Augustine says (QQ. Super Lev, qu. i), Moses in the
passage quoted did not state to whom one man had to denounce
another's perjury: wherefore it must be understood that the matter
had to be denounced "to those who would do the perjurer good rather
than harm." Again, neither did he state in what order the
denunciation was to be made: wherefore seemingly the Gospel order
should be followed, if the sin of perjury should be hidden,
especially when it does not tend to another person's injury: because
if it did, the Gospel order would not apply to the case, as stated
above (Q. 33, A. 7; Q. 68, A. 1).
Reply Obj. 4: It is lawful to make use of an evil for the sake of
good, as God does, but it is not lawful to lead anyone to do evil.
Consequently it is lawful to accept the oath of one who is ready to
swear by false gods, but it is not lawful to induce him to swear by
false gods. Yet it seems to be different in the case of one who
swears falsely by the true God, because an oath of this kind lacks
the good of faith, which a man makes use of in the oath of one who
swears truly by false gods, as Augustine says (ad Public. Ep. xlvii).
Hence when a man swears falsely by the true God his oath seems to
lack any good that one may use lawfully.
_______________________