FIRST ARTICLE [II-II, Q. 89, Art. 1]

Whether to Swear Is to Call God to Witness?

Objection 1: It would seem that to swear is not to call God to

witness. Whoever invokes the authority of Holy Writ calls God to

witness, since it is His word that Holy Writ contains. Therefore, if

to swear is to call God to witness, whoever invoked the authority of

Holy Writ would swear. But this is false. Therefore the antecedent is

false also.

Obj. 2: Further, one does not pay anything to a person by calling him

to witness. But he who swears by God pays something to Him for it is

written (Matt. 5:33): "Thou shall pay [Douay: 'perform'] thy oaths to

the Lord"; and Augustine says [*Serm. clxxx] that to swear (_jurare_)

is "to pay the right (_jus reddere_) of truth to God." Therefore to

swear is not to call God to witness.

Obj. 3: Further, the duties of a judge differ from the duties of a

witness, as shown above (QQ. 67, 70). Now sometimes a man, by

swearing, implores the Divine judgment, according to Ps. 7:5, "If I

have rendered to them that repaid me evils, let me deservedly fall

empty before my enemies." Therefore to swear is not to call God to

witness.

_On the contrary,_ Augustine says in a sermon on perjury (Serm.

clxxx): "When a man says: 'By God,' what else does he mean but that

God is his witness?"

_I answer that,_ As the Apostle says (Heb. 6:16), oaths are taken for

the purpose of confirmation. Now speculative propositions receive

confirmation from reason, which proceeds from principles known

naturally and infallibly true. But particular contingent facts

regarding man cannot be confirmed by a necessary reason, wherefore

propositions regarding such things are wont to be confirmed by

witnesses. Now a human witness does not suffice to confirm such

matters for two reasons. First, on account of man's lack of truth,

for many give way to lying, according to Ps. 16:10, "Their mouth hath

spoken lies [Vulg.: 'proudly']." Secondly, on account of [his] lack

of knowledge, since he can know neither the future, nor secret

thoughts, nor distant things: and yet men speak about such things,

and our everyday life requires that we should have some certitude

about them. Hence the need to have recourse to a Divine witness, for

neither can God lie, nor is anything hidden from Him. Now to call God

to witness is named _jurare_ (to swear) because it is established as

though it were a principle of law (_jure_) that what a man asserts

under the invocation of God as His witness should be accepted as

true. Now sometimes God is called to witness when we assert present

or past events, and this is termed a "declaratory oath"; while

sometimes God is called to witness in confirmation of something

future, and this is termed a "promissory oath." But oaths are not

employed in order to substantiate necessary matters, and such as come

under the investigation of reason; for it would seem absurd in a

scientific discussion to wish to prove one's point by an oath.

Reply Obj. 1: It is one thing to employ a Divine witness already

given, as when one adduces the authority of Holy Scripture; and

another to implore God to bear witness, as in an oath.

Reply Obj. 2: A man is said to pay his oaths to God because he

performs what he swears to do, or because, from the very fact that he

calls upon God to witness, he recognizes Him as possessing universal

knowledge and unerring truth.

Reply Obj. 3: A person is called to give witness, in order that he

may make known the truth about what is alleged. Now there are two

ways in which God makes known whether the alleged facts are true or

not. In one way He reveals the truth simply, either by inward

inspiration, or by unveiling the facts, namely, by making public what

was hitherto secret: in another way by punishing the lying witness,

and then He is at once judge and witness, since by punishing the liar

He makes known his lie. Hence oaths are of two kinds: one is a simple

contestation of God, as when a man says "God is my witness," or, "I

speak before God," or, "By God," which has the same meaning, as

Augustine states [*See argument On the contrary]; the other is by

cursing, and consists in a man binding himself or something of his to

punishment if what is alleged be not true.

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Summa Theologica, Part II-II (Secunda Secundae) Translated by Fathers of the English Dominican Province · 第 590 / 1128 题