Whether an Oath Has a Binding Force?
Objection 1: It would seem that an oath has no binding force. An oath
is employed in order to confirm the truth of an assertion. But when a
person makes an assertion about the future his assertion is true,
though it may not be verified. Thus Paul lied not (2 Cor. 1:15,
seqq.) though he went not to Corinth, as he had said he would (1 Cor.
16:5). Therefore it seems that an oath is not binding.
Obj. 2: Further, virtue is not contrary to virtue (Categ. viii, 22).
Now an oath is an act of virtue, as stated above (A. 4). But it would
sometimes be contrary to virtue, or an obstacle thereto, if one were
to fulfil what one has sworn to do: for instance, if one were to
swear to commit a sin, or to desist from some virtuous action.
Therefore an oath is not always binding.
Obj. 3: Further, sometimes a man is compelled against his will to
promise something under oath. Now, "such a person is loosed by the
Roman Pontiffs from the bond of his oath" (Extra, De Jurejur., cap.
Verum in ea quaest., etc.). Therefore an oath is not always binding.
Obj. 4: Further, no person can be under two opposite obligations. Yet
sometimes the person who swears and the person to whom he swears have
opposite intentions. Therefore an oath cannot always be binding.
_On the contrary,_ It is written (Matt. 5:33): "Thou shalt perform
thy oaths to the Lord."
_I answer that,_ An obligation implies something to be done or
omitted; so that apparently it regards neither the declaratory oath
(which is about something present or past), nor such oaths as are
about something to be effected by some other cause (as, for example,
if one were to swear that it would rain tomorrow), but only such as
are about things to be done by the person who swears.
Now just as a declaratory oath, which is about the future or the
present, should contain the truth, so too ought the oath which is
about something to be done by us in the future. Yet there is a
difference: since, in the oath that is about the past or present,
this obligation affects, not the thing that already has been or is,
but the action of the swearer, in the point of his swearing to what
is or was already true; whereas, on the contrary, in the oath that is
made about something to be done by us, the obligation falls on the
thing guaranteed by oath. For a man is bound to make true what he has
sworn, else his oath lacks truth.
Now if this thing be such as not to be in his power, his oath is
lacking in judgment of discretion: unless perchance what was possible
when he swore become impossible to him through some mishap, as when a
man swore to pay a sum of money, which is subsequently taken from him
by force or theft. For then he would seem to be excused from
fulfilling his oath, although he is bound to do what he can, as, in
fact, we have already stated with regard to the obligation of a vow
(Q. 88, A. 3, ad 2). If, on the other hand, it be something that he
can do, but ought not to, either because it is essentially evil, or
because it is a hindrance to a good, then his oath is lacking in
justice: wherefore an oath must not be kept when it involves a sin or
a hindrance to good. For in either case "its result is evil" [*Cf.
Bede, Homil. xix, in Decoll. S. Joan. Bapt.]
Accordingly we must conclude that whoever swears to do something is
bound to do what he can for the fulfilment of truth; provided always
that the other two accompanying conditions be present, namely,
judgment and justice.
Reply Obj. 1: It is not the same with a simple assertion, and with an
oath wherein God is called to witness: because it suffices for the
truth of an assertion, that a person say what he proposes to do,
since it is already true in its cause, namely, the purpose of the
doer. But an oath should not be employed, save in a matter about
which one is firmly certain: and, consequently, if a man employ an
oath, he is bound, as far as he can, to make true what he has sworn,
through reverence of the Divine witness invoked, unless it leads to
an evil result, as stated.
Reply Obj. 2: An oath may lead to an evil result in two ways. First,
because from the very outset it has an evil result, either through
being evil of its very nature (as, if a man were to swear to commit
adultery), or through being a hindrance to a greater good, as if a
man were to swear not to enter religion, or not to become a cleric,
or that he would not accept a prelacy, supposing it would be
expedient for him to accept, or in similar cases. For oaths of this
kind are unlawful from the outset: yet with a difference: because if
a man swear to commit a sin, he sinned in swearing, and sins in
keeping his oath: whereas if a man swear not to perform a greater
good, which he is not bound to do withal, he sins indeed in swearing
(through placing an obstacle to the Holy Ghost, Who is the inspirer
of good purposes), yet he does not sin in keeping his oath, though he
does much better if he does not keep it.
Secondly, an oath leads to an evil result through some new and
unforeseen emergency. An instance is the oath of Herod, who swore to
the damsel, who danced before him, that he would give her what she
would ask of him. For this oath could be lawful from the outset,
supposing it to have the requisite conditions, namely, that the
damsel asked what it was right to grant, but the fulfilment of the
oath was unlawful. Hence Ambrose says (De Officiis i, 50): "Sometimes
it is wrong to fulfil a promise, and to keep an oath; as Herod, who
granted the slaying of John, rather than refuse what he had promised."
Reply Obj. 3: There is a twofold obligation in the oath which
a man takes under compulsion: one, whereby he is beholden to the
person to whom he promises something; and this obligation is cancelled
by the compulsion, because he that used force deserves that the
promise made to him should not be kept. The other is an obligation
whereby a man is beholden to God, in virtue of which he is bound to
fulfil what he has promised in His name. This obligation is not
removed in the tribunal of conscience, because that man ought rather
to suffer temporal loss, than violate his oath. He can, however, seek
in a court of justice to recover what he has paid, or denounce the
matter to his superior even if he has sworn to the contrary, because
such an oath would lead to evil results since it would be contrary to
public justice. The Roman Pontiffs, in absolving men from oaths of
this kind, did not pronounce such oaths to be unbinding, but relaxed
the obligation for some just cause.
Reply Obj. 4: When the intention of the swearer is not the
same as the intention of the person to whom he swears, if this be due
to the swearer's guile, he must keep his oath in accordance with the
sound understanding of the person to whom the oath is made. Hence
Isidore says (De Summo Bono ii, 31): "However artful a man may be in
wording his oath, God Who witnesses his conscience accepts his oath as
understood by the person to whom it is made." And that this refers to
the deceitful oath is clear from what follows: "He is doubly guilty
who both takes God's name in vain, and tricks his neighbor by guile."
If, however, the swearer uses no guile, he is bound in accordance with
his own intention. Wherefore Gregory says (Moral. xxvi, 7): "The human
ear takes such like words in their natural outward sense, but the
Divine judgment interprets them according to our inward intention."
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