Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that an oath is not voided by a condition of person or time. An oath, according to the Apostle (Heb. 6:16), is employed for the purpose of confirmation. Now it is competent to anyone to confirm his assertion, and at any time. Therefore it would seem that an oath is not voided by a condition of person or time.

Objection 2: Further, to swear by God is more than to swear by the Gospels: wherefore Chrysostom says: "If there is a reason for swearing, it seems a small thing to swear by God, but a great thing to swear by the Gospels. To those who think thus, it must be said: Nonsense! the Scriptures were made for God's sake, not God for the sake of the Scriptures." Now men of all conditions and at all times are wont to swear by God. Much more, therefore, is it lawful to swear by the Gospels.

Objection 3: Further, the same effect does not proceed from contrary causes, since contrary causes produce contrary effects. Now some are debarred from swearing on account of some personal defect; children, for instance, before the age of fourteen, and persons who have already committed perjury. Therefore it would seem that a person ought not to be debarred from swearing either on account of his dignity, as clerics, or on account of the solemnity of the time.

Objection 4: Further, in this world no living man is equal in dignity to an angel: for it is written (Mt. 11:11) that "he that is the lesser in the kingdom of heaven is greater than he," namely than John the Baptist, while yet living. Now an angel is competent to swear, for it is written (Apoc. 10:6) that the angel "swore by Him that liveth for ever and ever." Therefore no man ought to be excused from swearing, on account of his dignity.

On the contrary, It is stated (II, qu. v, can. Si quis presbyter): "Let a priest be examined 'by his sacred consecration,' instead of being put on his oath": and (22, qu. v, can. Nullus): "Let no one in ecclesiastical orders dare to swear on the Holy Gospels to a layman."

I answer that, Two things are to be considered in an oath. One is on the part of God, whose testimony is invoked, and in this respect we should hold an oath in the greatest reverence. For this reason children before the age of puberty are debarred from taking oaths , and are not called upon to swear, because they have not yet attained the perfect use of reason, so as to be able to take a oath with due reverence. Perjurers also are debarred from taking an oath, because it is presumed from their antecedents that they will not treat an oath with the reverence due to it. For this same reason, in order that oaths might be treated with due reverence the law says (22, qu. v, can. Honestum): "It is becoming that he who ventures to swear on holy things should do so fasting, with all propriety and fear of God."

The other thing to be considered is on the part of the man, whose assertion is confirmed by oath. For a man's assertion needs no confirmation save because there is a doubt about it. Now it derogates from a person's dignity that one should doubt about the truth of what he says, wherefore "it becomes not persons of great dignity to swear." For this reason the law says (II, qu. v, can. Si quis presbyter) that "priests should not swear for trifling reasons." Nevertheless it is lawful for them to swear if there be need for it, or if great good may result therefrom. Especially is this the case in spiritual affairs, when moreover it is becoming that they should take oath on days of solemnity, since they ought then to devote themselves to spiritual matters. Nor should they on such occasions take oaths temporal matters, except perhaps in cases grave necessity.

Reply to Objection 1: Some are unable to confirm their own assertions on account of their own defect: and some there are whose words should be so certain that they need no confirmation.

Reply to Objection 2: The greater the thing sworn by, the holier and the more binding is the oath, considered in itself, as Augustine states (Ad Public., Ep. xlvii): and accordingly is a graver matter to swear by God than the Gospels. Yet the contrary may be the case on account of the manner of swearing for instance, an oath by the Gospels might be taken with deliberation and solemnity, and an oath by God frivolously and without deliberation.

Reply to Objection 3: Nothing prevents the same thing from arising out of contrary causes, by way of superabundance and defect. It is in this way that some are debarred from swearing, through being of so great authority that it is unbecoming for them to swear; while others are of such little authority that their oaths have no standing.

Reply to Objection 4: The angel's oath is adduced not on account of any defect in the angel, as though one ought not to credit his mere word, but in order to show that the statement made issues from God's infallible disposition. Thus too God is sometimes spoken of by Scripture as swearing, in order to express the immutability of His word, as the Apostle declares (Heb. 6:17).

Articulus 10

Argumentum 1

Ad decimum sic proceditur. Videtur quod iuramentum non impediatur per aliquam conditionem personae vel temporis. Iuramentum enim ad confirmationem inducitur, ut patet per apostolum, ad Heb. VI.

Sed cuilibet convenit confirmare dictum suum, et quolibet tempore. Ergo videtur quod iuramentum non impediatur propter aliquam conditionem personae vel temporis.

Argumentum 2

Praeterea, maius est iurare per deum quam per evangelia, unde chrysostomus dicit, si aliqua causa fuerit, modicum videtur facere qui iurat per deum, qui autem iurat per evangelium, maius aliquid fecisse videtur. Quibus dicendum est, stulti, Scripturae propter deum factae sunt, non deus propter Scripturas.

Sed cuiuslibet conditionis personae, et quolibet tempore, in communi locutione consueverunt iurare per deum.

Ergo multo magis licitum est eis iurare per evangelia.

Argumentum 3

Praeterea, idem non causatur ex contrariis causis, quia contrariae causae sunt contrariorum. Sed aliqui excluduntur a iuramento propter defectum personae, sicut pueri ante quatuordecim annos, et etiam illi qui semel fuerunt periuri. Non ergo videtur quod aliqui prohibeantur iurare vel propter dignitatem, sicut clerici; aut etiam propter temporis solemnitatem.

Argumentum 4

Praeterea, nullus homo vivens in hoc mundo est tantae dignitatis sicut Angeli, dicitur enim Matth. XI quod qui minor est in regno caelorum maior est illo, scilicet ioanne baptista adhuc in mundo vivente.

Sed Angelo convenit iurare, dicitur enim Apoc. X quod Angelus iuravit per viventem in saecula saeculorum.

Ergo nullus homo propter dignitatem debet excusari a iuramento.

Sed Contra

Sed contra est quod habetur II, qu. V, presbyter, vice iuramenti, per sanctam consecrationem interrogetur.

Et XXII, qu. V, dicitur, nullus ex ecclesiastico ordine cuiquam laico quidquam super sancta evangelia iurare praesumat.

Corpus

Respondeo dicendum quod in iuramento duo sunt consideranda.

Unum quidem ex parte dei, cuius testimonium inducitur. Et quantum ad hoc, debetur iuramento maxima reverentia. Et propter hoc a iuramento excluduntur et pueri ante annos pubertatis, qui non coguntur ad iurandum, quia nondum habent perfectum usum rationis, quo possint cum reverentia debita iuramentum praestare, et iterum periuri, qui ad iuramentum non admittuntur, quia ex retroactis praesumitur quod debitam reverentiam iuramento non exhibebunt. Et propter hoc etiam, ut iuramento debita reverentia exhibeatur, dicitur XXII, qu. V, honestum est ut qui in sanctis audet iurare, hoc ieiunus faciat, cum omni honestate et timore dei.

Aliud autem est considerandum ex parte hominis, cuius dictum iuramento confirmatur. Non enim indiget dictum hominis confirmatione nisi quia de eo dubitatur. Hoc autem derogat dignitati personae, ut dubitetur de veritate eorum quae dicit.

Et ideo personis magnae dignitatis non convenit iurare.

Propter quod dicitur II, qu. V, cap. Si quis presbyter, quod sacerdotes ex levi causa iurare non debent.

Tamen pro aliqua necessitate, vel magna utilitate, licitum est eis iurare, et praecipue pro spiritualibus negotiis. Pro quibus etiam iuramenta competit praestare in solemnibus diebus, quibus est spiritualibus rebus vacandum, non autem tunc sunt iuramenta praestanda pro rebus temporalibus, nisi forte ex magna necessitate.

Ad 1

Ad primum ergo dicendum quod quidam sunt qui dictum suum confirmare non possunt propter eorum defectum, et quidam sunt quorum dictum adeo debet esse certum quod confirmatione non egeat.

Ad 2

Ad secundum dicendum quod iuramentum, secundum se consideratum, tanto sanctius est et magis obligat quanto maius est id per quod iuratur, ut Augustinus dicit, ad Publicolam.

Et secundum hoc, maius est iurare per deum quam per evangelia. Sed potest esse e converso propter modum iurandi, utpote si iuramentum quod fit per evangelia, fiat cum quadam deliberatione et solemnitate; iuramentum autem quod fit per deum, fiat leviter et absque deliberatione.

Ad 3

Ad tertium dicendum quod nihil prohibet aliquid tolli ex contrariis causis per modum superabundantiae et defectus. Et hoc modo aliqui impediuntur a iuramento quia sunt maioris auctoritatis quam quod eos iurare deceat, aliqui vero quia sunt minoris auctoritatis quam quod eorum iuramento stetur.

Ad 4

Ad quartum dicendum quod iuramentum Angeli inducitur non propter defectum ipsius, quasi non sit eius simplici dicto credendum, sed ad ostendendum id quod dicitur ex infallibili dei dispositione procedere. Sicut etiam et deus aliquando in Scripturis iurans inducitur, ad ostendendum immobilitatem eius quod dicitur, sicut apostolus dicit, ad Heb. VI.