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Hugo Grotius (1583–1645). The Rights of War and Peace. 1901.

Book II

Chapter XIII: On Oaths

  • Efficacy of oaths among Pagans—Deliberation requisite in oaths—The sense, in which oaths are understood to be taken, to be adhered to—To be taken according to the usual meaning of the words—The subject of them to be lawful—Not to counteract moral obligations—In what sense oaths are an appeal to God—The purport of oaths—To be faithfully observed in all cases—The controul of sovereigns over the oaths of subjects—Observations on our Saviour’s prohibition of oaths—Forms substituted for oaths.

  • I. THE SANCTITY of an oath with regard to promises, agreements, and contracts, has always been held in the greatest esteem, in every age and among every people. For as Sophocles has said in his Hippodamia, “The soul is bound to greater caution by the addition of an oath. For it guards us against two things, most to be avoided, the reproach of friends, and the wrath of heaven.” In addition to which the authority of Cicero may be quoted, who says, our forefathers intended that an oath should be the best security for sincerity of affirmation, and the observance of good faith. “For, as he observes in another place, there can bee no stronger tie, to the fulfilment of our word and promise, than an oath, which is a solemn appeal to the testimony of God.”

    II. The next point, to be considered, is the original force and extent of oaths.

    And in the first place the arguments, that have been used respecting promises and contracts, apply to oaths also, which ought never to be taken but with the most deliberate reflection and judgment. Nor can any one lawfully take an oath, with a secret intention of not being bound by it. For the obligation is an inseparable and necessary consequence of an oath, and every act accompanied with an obligation is supposed to proceed from a deliberate purpose of mind. Every one is bound likewise to adhere to an oath in that sense, in which it is usually understood to be taken. For an oath being an appeal to God, should declare the full truth in the sense in which it is understood. And this is the sense upon which Cicero insists that all oaths should be performed and adhered to in that sense, in which the party imposeing them intended they should be taken. For although in other kinds of promises a condition may easily be implied, to release the promiser; yet that is a latitude by no means admissible in an oath. And on this point an appeal may be made to that passage, where the admirable writer of the Epistle to the Hebrews has said, GOD WILLING more abundantly to shew unto the heirs of the promise the immutability of his counsel confirmed it by an oath: that by two immutable things, in which it was impossible for God to deceive, we might have a strong consolation. In order to understand these words, we must observe that the sacred writers, in speaking of God, often attribute to him human passions, rather in conformity to our finite capacities, than to his infinite nature. For God does not actually change his decrees, though he may be said to do so, and to repent, whenever he acts otherwise than the words seemed to indicate, the occasion, on which they were delivered, having ceased. Now this may easily be applied in the case of threats, as conferring no right; sometimes too in promises, where a condition is implied. The Apostle therefore names two things denoting immutability, a promise which confers a right, and an oath, which admits of no mental reservations.

    From the above arguments it is easy to comprehend what is to be thought of an oath fraudulently obtained. For if it is certain that a person took the oath upon a supposition, which afterwards was proved to have no foundation, and but for the belief of which he would never have taken it, he will not be bound by it. But if it appears that he would have taken it without that supposition; he must abide by his oath, because oaths allow of no evasion.

    III. The meaning of an oath should not be stretched beyond the usual acceptation of words. Therefore there was no breach of their oath in those, who, having sworn that they would not give their daughters in marriage to the Benjamites, permitted those that had been carried off to live with them. For there is a difference between giving a thing, and not recovering that which is lost.

    IV. To give validity to an oath, the obligation, which it imposes ought to be lawful. Therefore a sworn promise, to commit an illegal act, to do any thing in violation of natural or revealed law, will be of no effect.

    V. Indeed if a thing promised upon oath be not actually illegal, but only an obstruction to some greater moral duty, in that case also the oath will not be valid. Because it is a duty which we owe to God not to deprive ourselves of the freedom of doing all the good in our power.

    VI. Oaths may differ in form, and yet agree in substance. For they all ought to include an appeal to God, calling upon him to witness the truth, or to punish the falsehood of their assertions, both of which amount to the same thing. For an appeal to the testimony of a superior, who has a right to punish, is the same as requiring him to avenge an act of perfidy. Now the omniscience of God gives him power to punish, as well as to witness every degree of falsehood.

    VII. It was a custom with the ancients to swear by persons or beings expressly distinct from the supreme creator, either imprecating the wrath of those by whom they swore, whether it were the sun, the heavens, or the earth; or swearing by their own heads, by their children, their country or their prince, and calling for destruction upon THEM, if there were any falsehood in their oaths.

    Nor was this practice confined to Heathen nations only, but, as we are informed by Philo, it prevailed among the Jews. For he says that we ought not, in taking an oath upon every occasion, to have recourse to the maker and father of the universe, but to swear by our parents, by the heavens, the earth, the universe. Thus Joseph is said to have sworn by the life of Pharaoh, according to the received custom of the Egyptians. Nor does our Saviour, in the fifth chapter of St. Matthew’s Gospel, intend, as it is supposed by some, to consider these oaths to be less binding than those taken expressly by the name of God. But as the Jews were too much inclined to make use of, and yet disregard them, he shews them that they are real oaths. For, as Ulpian has well observed, he who sears by his own life, seems to swear by God, bearing a respect and reference to his divine power. In the same manner Christ shews that he, who swears by the temple, swears by God who presides in the temple, and that he who sears by Heaven, swears by God, who sits upon the Heavens. But the Jewish teachers of that day thought that men were not bound by oaths made in the name of created beings, unless some penalty were annexed, as if the thing, by which they swore, were consecrated to God. For this is the kind of oath implied in the word [Greek], as BY A GIFT. And it is this error of theirs, which Christ refutes.

    VIII. The principal effect of oaths is to cut short disputes. “An oath for confirmation, as the inspired writer of the Epistle to the Hebrews has said, is the end of all strife.” So too we find in Diodorus Siculus, that an oath was regarded among the Egyptians as the surest pledge of sincerity that men could give. So that every one, in taking an oath, should express the real purpose of his mind, and render his actions conformable to those expressions. There is a beautiful passage on this subject, in Dionysius of Halicarnassus, who says, “the last pledge among men, whether Greeks or Barbarians, and it is a pledge, which no time can blot out, is that which takes the Gods, as witnesses to oaths and covenants.”

    IX. The substance of an oath too should be such, and conceived in such words, as to include not only the divine, but the human obligations, which it implies. For it should convey to the person, who receives it, the same security for his right, as he would derive from an express promise or a contract. But if either the words bear no reference to a person so as to confer upon him a right, or if they do refer to him but in such a manner that some opposition may be made to his claim, the force of the oath will, in that case, be such as to give that person no right from it; yet he who has taken it must still submit to the divine obligation, which the oath imposes. An example of which we have in a person, from whom a sworn promise has been extorted by fear. For here the oath conveys no right, but what the receiver ought to relinquish, for it has been obtained to the prejudice of the giver. Thus we find the Hebrew Kings were reproved by the prophets, and punished by God for not observing the oaths, which they had taken to the kings of Babylon.

    X. The same rule applies not only to transactions between public enemies, but to those between any individuals whatsoever. For he, to whom the oath is taken, is not the only person to be considered; but a solemn regard must be paid to God, in whose name the oath is taken, and who possesses authority to enforce the obligation. For which reason it is impossible to admit the position of Cicero, that it is no breach of an oath to refuse paying to robbers the sum stipulated for having spared one’s life; because such men are not to be ranked in the number of lawful enemies, but treated as the common enemies of all mankind, so that towards them no faith ought to be kept, nor even the sanctity of an oath observed.

    XI. The power of superiors over inferiors, that is of sovereigns over subjects, with respect to oaths, is the next topic that comes under consideration. Now the act of a superior cannot annul the perfect obligation of an oath, which rests upon natural and revealed law. But as we are not, in a state of civil society, entirely masters of our own actions, which in some measure depend upon the direction of the sovereign power, which has a two-fold influence with respect to oaths, in the one case applying to the person who takes, and in the other, to the person who receives them. This authority may be exercised over the person taking the oath, either by declaring, before it is taken, that it shall be made void, or by prohibiting its fulfilment, when taken. For the inferior or subject, considered as such, could not bind himself to engagements, beyond those allowed by the sovereign legislature. In the same manner, by the Hebrew Law, husbands might annul the oaths of wives, and fathers those of children, who were still dependent.

    XII. In this place we may cursorily observe, that what is said in the precepts of Christ, and by St. James, against swearing at all, applies not to an oath of affirmation, many instances of which are to be found in the writings of St. Paul, but to promissory oaths respecting uncertain and future events. This is plain from the opposition in the words of Christ. “You have heard it hath been said by them of old time, thou shalt not forswear thyself, but shalt perform unto the Lord thine oath. But I say to you, swear not at all.” And the reason given for it by St. James, is that “you fall not into hypocrisy,” or be found deceivers; for so the word HYPOCRISY signifies in the Greek.

    Again it is said by St. Paul, that all the promises of God in Christ are YEA and AMEN, that is are certain and undoubted. Hence came the Hebrew phrase, that a just man’s YEA is YEA, and his NO is NO. On the other hand, persons, whose actions differ from their affirmations, are said to speak YEA and NO, that is their affirmation is a denial, and their denial an affirmation. In this manner St. Paul vindicates himself from the charge of lightness of speech, adding that his conversation had not been YEA, and NO.

    XIII. Affirmations are not the only modes of obligation. For in many places signs have been used as pledges of faith; thus among the Persians giving the right hand was considered the firmest tie. So that where any form is substituted for an oath, the violation of it will be an act of perjury. It has been said of Kings and Princes in particular, that their faith is the same as an oath. On which account Cicero, in his speech for Dejotarus, commends Caesar no less for the vigour of his arm in battle, than for the sure fulfilment of the pledge and promise of his right hand.