The lawfulness of oaths

243. Definition. An oath, which is also called a sacrament, is customarily defined: the invocation of the divine name in testimony of truth.

a. Invocation is a petition by which God is asked that, by His infallible testimony, He will, when it shall please Him, in this life or in the other, manifest the truth of that which is asserted or promised. The end of an oath is the confirmation of truth by a testimony which exists as most firm, that is, infallible, and therefore the ending of controversy.² Invocation can be express or tacit, namely through mere external signs, such as the touching of the cross or of the Gospel, or the raising of the fingers made as a sign of an oath. Of the divine name: for an oath can be made only by God; for it was introduced for confirming truth by a testimony greater than every exception, or infallible; but the testimony of God alone is infallible.

b. An oath supposes faith concerning the existence of God and fear of God; wherefore the oaths of those who acknowledge God as omniscient and infallible, such as Jews, deists, etc., are true oaths; but the oaths of those who do not acknowledge the true God, such as pantheists, atheists, materialists, etc., have no value; finally the oaths of gentiles who swear by false gods are null, although accidentally from an erroneous conscience they can be obligated.

c. An oath, as soon as it has been uttered, produces its effect, namely it confirms the hearers concerning the truth of that which is affirmed or promised. For they reason thus: if it were not true, the one swearing, who is supposed to fear God, would not dare to invoke God as witness of his assertion, who can immediately manifest, or certainly will manifest in the other life, whether that which is affirmed or promised is true.

Note. From the peculiar end of an oath and from its supreme sanctity these things are to be inferred: a. that an oath is not to be exacted or admitted unless there is question of a great good, whether of the community or of some private person, lest a religious act, to the detriment of the common good, degenerate into a mere ceremony; b. that it is not to be exacted or admitted from those who are foreseen to be about to perjure themselves, nor from those who do not admit the existence of God (socialists, atheists); c. that those who from the doctrine of their sect in good faith reject an oath as illicit, and attribute the force of an oath to a simple assertion, are not to be compelled to swear, lest they be compelled to act against their conscience. It is clear that these are to be subjected to the penalties by which perjurers are punished, when it has been established that they knowingly confirmed a falsehood by the pledge of the right hand.

¹ St. Thomas, II-II, q. 89. St. Alphonsus, l. 3, n. 133-193. Suarez, De religione, tract. 5. Dicastillo, De iuramento. Sporer-Bierbaum, Theologia moralis decalog. (Paderbornae: Typographia bonifac., 1897), tract. 3, n. 7-172. Fr. Gopfert, Der Eid (Mainz: Kirchheim, 1883). Bouquillon, De virtute religionis (Bruges: Beyaert, 1880), pars III. Ballerini-Palmieri, Opus theolog. morale^3, II, n. 532-601.

² Heb. 6:16.

244. Liceity. 1. The liceity of an oath, from the Pelagians down to the Jansenists, many have denied, each from various reasons.¹

From the proper end of an oath it is established that it is not to be sought on account of itself, but is a means of assisting some defect, namely by which one man does not believe another. For this reason an oath is licit not absolutely, but only relatively, namely when it becomes either necessary or useful for its proper end. But that an oath clothed with the due conditions is licit and honorable is certain from faith.

a. Sacred Scripture approves an oath: alpha. of the Old Testament: Thou shalt fear the Lord thy God and shalt serve Him alone, and thou shalt swear by His name;² beta. it determines the conditions of a licit oath: And thou shalt swear ... in truth and in judgment and in justice;³ gamma. and it attributes an oath to the Lord God Himself: By My own self I have sworn, saith the Lord; because thou hast done this thing ... I will bless thee.⁴

b. From the books of the New Testament we know that St. Paul often swore: God is my witness ... that without ceasing I make a commemoration of you.⁵

c. From the use and practice of the Church it is established that an oath is not only permitted, but is often even prescribed.

d. An oath by its nature is an act of the virtue of religion: for through it we acknowledge and profess a twofold divine perfection, namely His infallible omniscience and His veracity, by the profession of which we exhibit reverence to God; but to exhibit reverence to God is an act of religion or an act of the worship of latria.

2. From these things it is clear that the words of sacred Scripture,⁶ by which an oath seems to be forbidden to Christians, from the interpretation of the Church are to be understood not of an absolute prohibition, but of a prohibition for the state of Christian perfection.

And indeed by these words it is signified that an oath is not good and to be sought of itself, but is from evil (it is not said: it is evil): for its necessity has arisen both from the unbelief of hearers and from defect of truthfulness in speakers. But Christians ought to be of such perfection that an oath is rendered altogether superfluous, and the same faith can be given to their simple affirmation or negation as to an oath.⁷

Note. a. It is not lawful for ecclesiastics to interpose a solemn oath before a lay judge without the license of the bishop; b. a parish priest cannot exact a solemn oath from a parishioner except in the name and by the authority of the bishop; c. impubescent persons cannot be compelled to a solemn oath;⁸ d. an oath can also be interposed through a procurator.

¹ Cf. Gopfert, Der Eid, p. 111 ff.

² Deut. 6:13.

³ Jer. 4:2.

⁴ Gen. 22:16-17. Cf. Ps. 131:11.

⁵ Rom. 1:9. Cf. 2 Cor. 1:23; Gal. 1:20.

⁶ Matt. 5:33 ff.; Jas. 5:12.

⁷ Cf. Knabenbauer, Cursus scripturae sacrae (Parisiis: Lethielleux), on Matthew, c. 5, 33 ff.

⁸ C. Pueri 15, c. 22, q. 5.

245. Division. a. By reason of matter, an oath is divided into assertory, by which God is invoked as witness of a past or present thing: I swear that I gave alms; I swear that I am a Catholic; and into promissory, by which God is invoked as witness of a future thing: I swear that I will give alms.

It is called promissory because for the most part it is used for confirming a promise made to another.

b. By reason of form, into invocatory, by which God is invoked only as witness of truth; and into imprecatory (execratory), by which God is invoked as witness of truth and avenger of perjury: for the one swearing imprecates evils upon himself or his own, if he asserts a falsehood, or if he does not keep that to which he obligates himself.

alpha. An execratory oath is customarily made in two ways: either by directly imprecating: may I be struck by lightning, if it is not true; or by interposing some good which may perish if a falsehood is sworn: by my life, by my salvation.¹

beta. The formula which is customarily used in both ecclesiastical and forensic oaths: So may God help me and these holy Gospels of God, is a formula of an imprecatory oath and is to be explained in this way: if what I swear is true, may God help me; if it is false, may God deprive me of His help.

c. By reason of the term, into explicit, by which God Himself is immediately invoked as witness: God is my witness;² and into implicit, by which immediately a creature is invoked, which nevertheless has a special relation to God, because the divine attributes specially shine forth in it: I invoke heaven and earth as witnesses today;³ for he who swears by the saints, by heaven and earth, invokes God shining forth in them.

d. By reason of mode, into solemn, which is made with some external solemnity, for example before a crucifix, with candles lit, before witnesses, by touching the Gospel or a scepter, by raising the first fingers, etc.; and into simple, which is made without external solemnity.

All these diverse oaths are of the same moral species, for all agree in the formal nature of oath, which is the invocation of the divine name; but the diverse mode of invocation by which they differ from one another is accidental and therefore does not change their specific essence.

¹ Suarez, l. 1, c. 12, n. 9.

² Rom. 1:9.

³ Deut. 30:19.

If the requisite conditions be fulfilled, oaths are lawful, and indeed they are an act of divine worship, for they are an acknowledgement of the omniscience and veracity of God, as well as a public profession of belief in him. This has been the constant teaching of the Church, teaching which has ample warrant in both the Old and New Testament, The prophet 1$7 Jeremias lays down the conditions which justify an oath, and many instances of oaths are found in the epistles of the Apostle of the Gentiles. The words of our Lord¹ do not prohibit the taking of oaths if the requisite conditions be present. They give expression to his desire that all Christians should be so truthful and sincere that it will not be necessary for them to use oaths to confirm the truth of what they assert. The conditions which make an oath lawful are given in the words of Jeremias:² ‘‘ And thou shalt swear, As the Lord liveth, in truth, and in judgement, and in justice.”

We swear in truth when we are morally certain that what we assert under oath is according to fact. We are not justified in asserting that to be true which we do not know to be true and we commit the grave sin of perjury if we swear to what we know to be false.

We swear with judgement when there is a just cause for invoking the testimony of God and it is done with proper consideration and reverence. A just cause will be any matter of some importance for the welfare of either soul or body, whether it be public or private. We are not, therefore, justified in swearing to every assertion which we believe to be true; there must be some special reason for employing the name and authority of God to confirm what we say. However, provided that the other conditions are not wanting, the defect of judgement in swearing will not be more than a venial sin, for it is no more than the idle use of the name of God.

It is an insult to God to invoke his testimony to a sinful act or in furtherance of what is sinful. If this is done, the oath is unlawful on account of the want of justice. Justice, then, in this connection requires that the assertion in an assertory oath should not be sinful, such as a sin of detraction or boasting about past sins. In a promissory oath, that which is promised must be honest and lawful.

There is some difficulty and dispute among theologians about the gravity of the sin which is committed when an oath wants justice. If in an assertory oath the testimony of God is unjustifiably invoked to promote a seriously sinful object, the want of justice in the oath will be gravely sinful. If, on the contrary, the testimony of God does not further the end in view, the want of justice will probably be only venially sinful, because the assertion is true, as is here presumed, and the irreverence committed against God by invoking his testimony even to a gravely sinful act does not seem to many to be more than a venial sin.

An oath, therefore, taken to confirm detraction in a grave matter is mortally sinful; an oath confirming a boast about grave sins committed in the past is probably only venial.

Somewhat similarly in a promissory oath, if the act promised be gravely sinful, the defect of justice makes the oath gravely sinful; for it is a great insult to God to use his testimony to further what is mortally sinful. If the act promised is only a venial sin, a probable opinion holds that the oath is only venially sinful, against a more probable contrary view.

¹ Matt. v 34.

² Jer. iv 2.

Lawfulness of Oaths.—(a) It is lawful to take an oath that has the necessary qualities, for in Scripture God Himself is represented as swearing (Gen, xxii. 16; Psalm cix. 4, Heb., vi. 13, vii. 21), holy men swear and are praised for swearing as they should (II Cor., i. 23; Psalm xiv. 4), and the Church has always made use of oaths. The origin of oaths is man’s faith in God, and their purpose is the useful one of lending authority to important assertions. Indeed, an oath is an act of religion, for men swear only by one who is greater (Heb., vi. 13), and hence an oath is a profession of reverence for God’s superior knowledge, truth, and justice.

(b) It is not lawful to take an oath that lacks a necessary quality. Here we should note an important difference between an oath and other acts of religion, such as vows. An oath is not desirable for its own sake, since it is occasioned by human weakness and unreliability; hence, like medicine and other necessities occasioned by evil, it should be used only in serious need and sparingly. A vow or other act of religion, on the contrary, originates from the desire to honor God, even apart from necessity, and hence it may be used oftener. This explains why Scripture forbids the habit of swearing (Ecclus., xxiii. 9; Matt., v. 33; James, v. 12); but it is a wrong interpretation of these texts that sees in them an absolute prohibition of oaths. From the context and other passages it is clear that the Scriptures just cited reprove the Pharisees who taught that promiscuous swearing was lawful, provided only the matter was true or the Divine Name was not used, and also those persons who delighted to swear on all occasions.

Necessary Qualities of a Lawful Oath.—The necessary qualities that should accompany an oath are expressed in Jeremias, iv. 2: “And thou shalt swear, ‘As the Lord liveth,’ in truth, and in judgment and in justice.” Judgment refers to the good dispositions of the person who swears, truth and justice to the righteousness of the cause for which he swears.

(a) Thus, an oath should have judgment; that is, the person who swears should do so only from serious necessity, with faith and devotion, and in a manner respectful to God whom he invokes. An oath that lacks judgment is called incautious or disrespectful, as when one swears about a trivial matter or swears jokingly.

(b) An oath should have truth; that is, one should not swear except to that which one believes to be true, after reasonable diligence has been used in seeking for the truth. An oath that lacks truth is called false or perjured, as when one swears to what one knows or believes to be false, or promises what one does not intend to fulfill, or swears that one is certain when one has only opinion, or swears with a purely mental reservation, or swears after insufficient investigation of a matter.

(c) An oath should have justice; that is, one should not promise what one has no right to promise (e.g., to tell a lie), and one should not say what one has no right to say (e.g., what is defamatory). The matter of the oath, then, both as to its object and its circumstances, must be good, even though one is swearing truthfully and respectfully. An oath that lacks justice is called a wicked oath, as when one promises under oath to commit murder, or not to follow what is of counsel, or swears about a real fact in such a way as to do unnecessary harm to another person or to boast about one’s own crimes.

Sinful Oaths.—(a) An incautious or disrespectful oath is from its nature only a venial sin, since its malice consists, not in any direct injury to the divine truth or other attribute, but only in levity of mind; and, moreover, it is not opposed to the purpose of an oath, which is to confirm the truth. But accidentally it may be a serious sin on account of the scandal it gives (e.g., when a person of standing swears without necessity), or on account of the danger to which it exposes the swearer (e.g., when one swears habitually and is thereby put in the occasion of swearing falsely or unjustly). On account of the evils of familiarity, etc., to which habitual swearing leads, Our Lord warn us to be content as a rule to support the truth with simple assertion or denial (Matt., v. 2). At least for ordinary, daily communications the word of a Christian or honest man ought to be sufficient without his oath.

(b) A lying or perjured oath is from the nature of the act always (see 172) a mortal sin, since it consists essentially in contempt for God and disrespect for His attributes. The perjurer dares to ask God to be an accomplice in a lie, or else supposes that God can be deceived. Hence, only by reason of the imperfection of the act can perjury ever escape the guilt of mortal sin, as when one commits perjury without sufficient reflection on or full consent to the oath or to its falsity. Pope Innocent XI condemned the doctrine that perjury is only a light sin (Denzinger, n. 1174). In Canon Law those who perjure themselves are debarred from acting as witnesses or giving expert testimony, and are subject to penalties at the discretion of the Ordinary (see Canons 1757, 1795, 2323). In American civil law perjury is a false oath given before a tribunal and is a crime against public justice, while subornation of perjury and false oaths given on private occasions are also crimes or punishable offenses.

(c) A wicked oath, even though the thing sworn to be true and the oath be given only after consideration and in a respectful manner, is a sin against religion and any other virtue it offends. The sin committed by reason of the oath is from its nature mortal according to some, since the swearer gravely insults God by asking Him to become a partaker in sin and by turning into an instrument of sin what should be an act of religion; others hold that the sin is only venial, since it is not serious disrespect to ask God to witness the truth of what is true; others again make the gravity of the sin depend on the wickedness of the matter or circumstances. This wickedness committed by reason of the statement or promise is venial or mortal according to the case. Thus, there is grave injustice in revealing a fact seriously detrimental to another and which one is bound to keep as confidential; there is venial scandal in swearing in order to lead another person into a slight fault of detraction; there is a grave sin of impurity in promising to commit adultery; there is a light sin of theft in promising to steal a small sum of money. Finally, others hold that the oath is mortally sinful when it furthers a grave sin (e.g., an oath confirming serious detraction), and that it is venial in other cases (e.g., an oath confirming a boast about past mortal sins).

Mental Reservation in an Oath.-(a) Strict mental reservation (i.e., the internal restriction of one’s words so that the listener cannot gather the true meaning, as when one says one has seen Rome, meaning a picture of Rome) is a lie, and hence cannot be used in an oath without perjury. See propositions condemned by Innocent XI (Denzinger, n. 1176).

(b) Wide mental reservation (i.e., the internal restriction of one’s words that may be gathered by the listener from circumstances, as when a servant says his master is not at home, meaning that he cannot be seen) is lawful only when there is some reason of justice or charity that demands it. Hence, it is a mortal sin to swear with this kind of reservation when the questioner has the right to know the truth; it is no sin at all when the questioner has no right to question and mental reservation is the only escape from a serious evil. If the questioner has no right to demand an oath and the deponent has no right to use mental reservation (e.g., when the oath is only private and not concerned with contract or other important matter), the sinfulness of a mental reservation is a matter of dispute. Some think the oath is mortally sinful, because it is gravely irreverent to God to call on Him to witness testimony meant to deceive. Others think the oath is only venially sinful, because the offense is not against truth or justice, but only against judgment or discretion.

Cooperation in Sinful Oaths.—(a) Formal cooperation is never lawful, because it makes the cooperator will the guilt of what is done. Thus, he who by command, counsel, promise, etc., induces another to swear falsely is guilty as the principal or accessory to the crime (see 1513, 1778).

(b) Material cooperation is lawful when there is a sufficient reason for it, as when a public official demands the oath according to law from a person who, as he knows, will swear falsely. For the public good demands that in certain cases oaths be administered, notwithstanding that for some persons this will prove an occasion of perjury. But the lawgiver should not multiply temptations by demanding sworn statements unnecessarily; otherwise the oath becomes a mere formality deprived of proving value, and the crime of perjury is made common.

Sinful Oaths Demanded or Accepted by Private Persons.—(a) Incautious or Disrespectful Oaths.—It is not lawful to ask or receive an oath, when there is no great public or private need for it; otherwise one makes a sacred act cheap and common. Neither is it lawful to ask or receive an oath from those who do not believe in oaths (e.g., the Mennonites, some Quakers); otherwise one compels another to swear against his conscience and indevoutly. Those who believe that oaths are sinful may be required, nevertheless, to bind themselves on their solemn word of honor, and may be punished in the same manner as perjurers if they speak falsely.

(b) Perjured Oaths.—It is not lawful for a private person to ask or receive an oath from another, if he is sure that the latter will commit perjury; but one may ask and receive an oath, even though one does not know whether the other person will swear truly or not, if one has a sufficient reason.

(c) Wicked Oaths.—It is clearly unlawful to ask or receive a wicked oath, in which something sinful is promised or stated; for the thing itself is then desired and there is formal cooperation. But it is not necessarily sinful to ask or receive a wicked oath, in which the sinfulness is found, not in the matter of the oath, but in the dispositions of the swearer, for there may be only material cooperation. Thus, he who exacts a sworn promise of murder agrees to murder, but he who demands a sworn statement against a third party for which there is necessity does not necessarily agree to hatred, if the person taking the oath swears out of hate or revenge.

Fictitious Oaths.—A fictitious oath is one in which a person swearing externally has no intention internally to call on God as a witness.

(a) This kind of oath is invalid, for, as was just said, without a real intention to swear there is no oath. Hence, a fictitious oath produces no obligation of religion, but there may be an obligation of justice, as when the oath is the unjust cause of damage to another.

(b) This kind of oath is sinful, for, if it testifies to error, it includes the grave sin of external dishonor to God; if it testifies to truth, it includes the venial sin of taking God’s name in vain. The fictitious oath is a grave sin if the circumstances are such that a sincere oath is gravely obligatory, as when a superior or judge lawfully imposes an oath in a serious matter, or the parties to an important onerous contract bind themselves by oath in order to strengthen their pact.

Expressions Confused with Oaths.—Expressions that are sometimes mistakenly confused with sinful swearing are the following: (a) profane or vulgar talk, such as “Hell,” “The devil,” “Doggone it”; (b) cursing, such as “Go to hell,” “God damn you,” “Damn it”, (e) contumely, such as “bastard,” “son of a bitch”; (d) vain use of the name of God, such as “by God,” “Christ,” etc., when used as common exclamations; (e) temptation of God, such as: “If there is a God, may He strike me dead!”; (f) blasphemy, such as: “May God perish, if this is not true!”

The expressions, “This is as true as the Gospel,” “God’s own word is not more truthful,” “I am as innocent as the Blessed Virgin,” etc., if used to confirm the truth, are not meant to assert the speaker’s equality to God and the Saints, and hence they are venial sins of taking the Lord’s name in vain. But, if they are used to confirm error, they are mortal sins of blasphemy.

Is an oath licit? - An oath clothed with due conditions is honorable and licit; and, if it is promissory, it obliges in conscience, unless a just cause stands in the way, or its obligation has legitimately ceased. This is established both from the definition of the Council of Constance, sess. 8, against Wyclif, and from proposition 101 condemned by Clement XI in the Bull Unigenitus, and from proposition 75 condemned by Pius VI in the Bull Auctorem fidei, and also from the universal practice of the Church and peoples, and from various places of Sacred Scripture. Deut. 6:13: You shall fear the Lord your God... and by his name you shall swear. And indeed God and his attributes are especially honored from this, that he is brought into the midst and invoked as the highest and infallible Truth in testimony of truth. C. Etsi 26, de Iurei.; L. 144 seqq.; S. Th. 2. 2, q. 89, aa. 3, 4. From a grave cause, and with a protestation employed, an oath upon Protestant Bibles can be permitted, insofar namely as they contain the true word of God. E. M.

What are the requisites for the licitness of an oath? - A threefold condition is required, according to Jer. 4:2: You shall swear: The Lord lives, in truth, and in judgment, and in justice. The reason is that otherwise it cannot be furnished with due reverence to God.

Truth, that is, conformity of the assertion with the knowledge and intention of the one swearing. Therefore it excludes every lie, but not every error. In an assertory oath, truth regards the existence of the fact according to the mind, not also according to the truth of the thing; in a promissory oath, it regards the existence of the intention of obliging oneself and of furnishing what is promised.

Judgment, that is, that it be done with discretion, prudence, consideration, and reverence, and not without necessity or a grave cause. For since an oath is a most holy thing, it ought not be made without prudence, consideration, reverence, and rashly without any necessity and cause.

Justice, that is, that the oath be concerning a matter, whether promised or simply proposed, or concerning an assertion, just and honorable. Thus he would swear against justice who would oblige himself by oath to inflict harm unjustly upon a neighbor, or would affirm what he was prohibited from manifesting. Ecclus. 23:9, 12; L. 144; S. Th. 2. 2, q. 89, aa. 3, 5, 10; E. M.

What is a sufficient cause for swearing? - Any honorable cause of some weight, for example, peace to be confirmed in families, greater security in contracts, etc. L., H. A. 14.

Is it permitted to swear with probability of truth? - "For swearing rightly absolute and altogether infallible certitude is not required, but some moral certitude suffices, or a certain probability which reaches a certain moral certitude. Thus Tamburini. Indeed Sanchez, Suarez, the Salmanticenses, Lessius, Bonacina, Azor, with the common opinion, say more expressly that in an oath, whether assertory or promissory, probability of the truth asserted or of the fulfillment of the promised thing to be executed suffices, provided that there is not a probable reason to the opposite. Hence they say that what has been heard from a person so worthy of faith that he makes us morally certain can indeed be affirmed with oath. Yet this does not run in judgment," L. 148, where the oath which is required is to be emitted from one's own certitude. Struggl 6. Therefore he sins gravely who swears in mere doubt of truth, because God, infallible truth, cannot be invoked except in testimony of a thing which seems at least morally certain. Struggl 6; S. Th. 2. 2, q. 89, a. 7 ad 1.

Is it permitted to swear with mental restriction? - R. Negative, if it is purely mental; and here, according to St. Alphonsus, pertain propositions 26, 27, 28 condemned by Innocent XI. Affirmative, if it is broadly mental, from a just cause. "It is certain," says St. Alphonsus, n. 151, "and common among all, that from a just cause it is permitted to use equivocation... and to confirm it by oath...

But a just cause can be any honorable end for preserving goods useful to spirit or body." And again: "For swearing thus, except in judgments and contracts, an absolutely grave cause is not required, but any reasonable cause suffices, for example, to free oneself from the troublesome and unjust interrogation of another." And Busembaum, n. 170, adds: "When there is a just cause of necessity or utility, one can use amphibologies in an oath, even if he spontaneously offers himself to the oath." Finally St. Alphonsus, n. 151, adds that, according to the more probable opinion, it is venial if he furnishes this without cause. "The reason is that in an oath of this sort truth and justice are already present, and only judgment or discretion is lacking; and the deficiency of this is only venial... Yet one must except, with the Salmanticenses and others commonly, unless this is done in judgment or in contracts." The reason of this exception as to the first is that we are bound from obedience to answer a superior legitimately interrogating according to the sense of the one interrogating; but as to the second, because then from justice we are bound to utter words according to the mind of the contracting party, lest he be deceived and suffer harm. Struggl 16 seqq.; Lugo, de Fid., d. 4, n. 67; S. Th. 2. 2, q. 89, a. 7 ad 4; E. M.

946. Certain heretics contended that oath is prohibited under the new law, among whom were the Waldenses and certain Protestants, such as the Quakers, relying on these words of the Lord: "Again you have heard that it was said to them of old: Thou shalt not forswear thyself... But I say to you not to swear at all, neither by heaven, for it is the throne of God; nor by the earth, for it is His footstool; nor by Jerusalem, for it is the city of the great King; neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your speech be: yea, yea; no, no; and that which is over and above these is of evil."² Nevertheless not only Catholics, but most Protestants, hold that an oath is licit, certain conditions being posited.

² Matt. 5:33-37.

947. 1. Thesis: An oath, clothed with the due conditions, is honest and laudable.

(A) That oath was in use under the old Law and approved by God Himself is clear from many texts:³ "Thou shalt fear the Lord thy God, and shalt serve Him only, and shalt swear by His name." In the new law likewise oath is often exhibited as something honest, used by the apostles; thus Paul writes:⁴ "For God is my witness, whom I serve in my spirit in the Gospel of His Son, that without ceasing I make a commemoration of you... But I call God to witness... For God is my witness, how I long after you all in the bowels of Jesus Christ." Wherefore, unless a contradiction is admitted between the words of Christ and the words of Paul, it must be said that the passage cited above is to be understood of the prohibition of swearing without cause, without necessity; for in common circumstances it is not necessary to confirm by oath the truth of the things which are said; for Christians ought to be so sincere that, even without any oath, their words are believed confidently.

³ Deut. 6:13; cf. Josh. 9:15; Judg. 21:5; Ps. 14:4 and 62:18, etc.

⁴ Rom. 1:9; 2 Cor. 1:23; Phil. 1:8.

(B) The practice of the Church has approved this interpretation; for in judgments, whether ecclesiastical or secular, oath is frequently used, either so that witnesses may be induced by religion to manifest the truth completely, or to strengthen an argument otherwise incomplete. And deservedly; for, provided God is invoked as witness of the truth brought forth not frequently, but only in a matter of great moment, no irreverence is committed against Him, but on the contrary His supreme veracity is acknowledged, and His justice, which strictly pursues and chastises perjury. Wherefore in the Epistle to the Hebrews it is read:⁵ "For men swear by one greater than themselves, and an oath for confirmation is the end of all their controversy."

⁵ Heb. 6:16.

948. 2. Conditions, moreover, are required for the liceity of an oath. Three are deduced from this text of Jeremiah,⁶ namely truth, judgment, and justice: "And thou shalt swear: As the Lord liveth, in truth, and in judgment, and in justice."

⁶ Jer. 4:2.

(A) Truth, that is, conformity of words with the knowledge and intention of the one swearing. Therefore it excludes a lie in asserting or promising, and fiction, or an oath uttered without the mind of swearing or obliging oneself.

(a) He who by oath confirms that which he knows to be false commits the mortal sin of perjury, because he commits grave irreverence against God, bringing Him in as witness of falsity. Nor does lightness of matter excuse here; for, even in light or joking matter, it is gravely repugnant to invoke God as witness of falsity. Therefore this proposition 24 was deservedly reproved by Innocent XI, March 2, 1679: "To call God as witness of a light lie is not such irreverence on account of which He wills or can damn a man."⁷

⁷ Apud Denzinger, n. 1041; Viva, on this proposition.

(b) It is not licit to swear with only probable knowledge of the matter, but moral certainty is required, namely that against which no prudent doubt fights; one swearing with prudent doubt concerning the truth sins mortally, because he inflicts grave irreverence upon God, by invoking Him as witness of something about which he doubts.

949. (c) Nor is it licit to swear with a mental restriction whose sense cannot be detected; indeed not even with a mental restriction whose sense can be detected, except from a most grave cause: for the former restriction is a lie; the latter is a distorted mode of speaking, which, when an oath accedes to it, can be used only in a case of true necessity, namely when there is no other means of protecting oneself or others against unjust aggression or a most grave evil.⁸ - Therefore these propositions were deservedly condemned by Innocent XI:

⁸ For understanding this, see what we wrote concerning lying, De Justitia, n. 408-417. - If the theory of equivocations and restrictions is rejected, and with moderns it is admitted that false speech is licit in a case of necessity, it must be said that false speech cannot be confirmed by oath, unless when there is no other means of averting a most grave harm, for example the death of an innocent person.

26. "If someone, either alone or before others, whether questioned, or of his own accord, whether for the sake of recreation, or for any other end, swears that he has not done something which in reality he has done, understanding within himself something which he did not do, or another way than that in which he did it, or any other true addition, he in reality does not lie, nor is he perjured."⁹

⁹ Here there is question, from the context, of a purely mental restriction, whose sense cannot be detected by a prudent man.

27. "A just cause of using these amphibologies is whenever this is necessary or useful for the health of the body, honor, preserving family goods, or for any other act of virtue, so that the hiding of truth is then judged expedient and studious."

28. "He who, by means of custom or gift, has been promoted to a magistracy or public office, will be able with mental restriction to take the oath which, by command of the king, is customarily exacted from similar persons, no regard being had to the intention of the one exacting it: because he is not bound to confess a hidden crime."¹⁰

¹⁰ As Viva testifies (on this proposition), thus is condemned the practice of those who use equivocation whenever, by command of legitimate authority, they swear that they were not promoted because of recommendations or gifts.

950. (d) He who promises something by oath without the intention of swearing or obliging himself, and therefore simulates an oath, commits a grave sin from its genus; for although he does not emit an oath, he uses the name of God in vain, and deceives others. Wherefore if this is done before a judge, or in contracts, the sin is grave. But in other matters of slight moment, the sin is probably light, according to many theologians, because it is nothing other than the vain use of the name of God. But all fictions of this kind, as unworthy of an honorable man and easily drawing one to perjury, are altogether to be avoided. - But he who with the mind of swearing promises something, yet without the intention of fulfilling it, sins mortally, since he brings God in as guarantor of a false promise.

951. (B) Justice, in an assertory oath, requires that the one swearing have the right of asserting what he says, and, in a promissory oath, that the thing promised be honest.

(a) Thus, in an assertory oath, he sins who manifests another's hidden crime without cause, or boasts of a sin committed: for he does not have the right of saying these things, nor, a fortiori, of confirming them by oath. Moreover, the gravity of the sin depends both on the intention of the agent and on the gravity of the things which are said.

(b) In a promissory oath, he certainly sins mortally who swears that he will commit some grave thing: for he inflicts a grave injury upon God by making Him witness and, as it were, guarantor of this iniquity. But if the act which is promised under the faith of an oath is only venially evil, the malice against religion is probably only venial, although, according to St. Alphonsus (n. 146) and others, it is more probably mortal, on account of the injury inflicted upon God. Whatever the case, oaths of this kind are carefully to be avoided, not only because of the reverence due to God, but because they savor of foolishness: for who of sound mind can invoke God as witness of the promise of a thing less honest?

952. (C) Judgment, or discretion, requires two things, namely, that there be a just cause for swearing, and besides that the oath be furnished with that reverence, internal and external, which the divine majesty requires.

(a) Therefore they sin who frequently swear, without sufficient reason, that is, without necessity or great utility: "Let not thy mouth be accustomed to swearing; for in it there are many falls... A man that sweareth much shall be filled with iniquity, and a scourge shall not depart from his house. And if he make it void, his sin shall be upon him; and if he dissemble, he offendeth doubly; and if he swear in vain, he shall not be justified."¹ Moreover, the gravity of the sin depends both on the frequency of the acts and on the intention of the agent; to swear once or twice without sufficient cause does not exceed venial sin, unless contempt of the divine majesty is present.

¹ Ecclus. 23:9-14.

(b) They also sin who utter oaths jokingly or in a manner little becoming. This happens by no means rarely when they are taken too frequently.² - Civil authority can indeed, from a just cause, exact an oath to be taken upon a book of Scripture; but it ought to permit Catholics to swear upon Catholic Bibles.³

² In the United States of America oaths are perhaps required too often in the matter of tributes and taxes; whence it happens that perjuries are easily committed in this matter. By a very excellent counsel all Christians ought to join their forces, so that they might obtain a change of the civil laws in this matter.

³ To the point, S. Cong. de Prop. Fide, Sept. 8, 1869 (Collectanea, n. 1664): "It has been reported that, in several regions of India, Catholics have been accustomed, if an oath occurs, to swear upon Bibles corrupted by Protestants and presented by the government... Therefore let all Apostolic Vicars, in whose missions use of this kind has been accustomed to be employed, diligently take care that the Anglo-Indian government leave to the faithful the liberty of swearing upon Sacred Scripture received by the Catholic Church. But until they shall have obtained this from the civil authority, let them prudently be silent, if they see the faithful take an oath upon the Bibles of heretics, provided that there is question of a lawful oath."

That oaths are lawful cannot simply be deduced from the fact that they are acts of divine worship, for they are not usually taken for the purpose of honoring God. The lawfulness of oaths was denied by some of the Church Fathers and ecclesiastical writers, by certain ancient and medieval sects which pretended to restore Christianity to its pristine purity, and by sundry Protestant denominations. All of them maintain that oaths are forbidden by the Bible. The principal texts which they cite in support of their contention are the following: a) Christ says: ‘You have heard that it was said to them of old, Thou shalt not forswear thyself: but thou shalt perform thy oaths to the Lord. But I say to you not to swear at all, neither by heaven, for it is the throne of God: nor by the earth, for it is his footstool: nor by Jerusalem, for it is the city of the great king. Neither shalt thou swear by thy head, because thou canst not make one hair white or black.

But let your speech be yea, yea: no, no: and that which is over and above these, is of evil (from evil).”¹ b) St. James writes: ‘Above all things, my brethren, swear not, neither by heaven, nor by earth, nor by any other oath. But let your speech be, yea, yea: no, no: that you fall not under judgment.”²

¹ Matt. V, 33–37.

² Jas. V, 12; cfr. Ex. XX, 7; Lev. XIX, 12; Numb. XXX, 3.

2. These texts, it is asserted, not only forbid wanton, false, and unjust swearing, or swearing by creatures instead of by the Creator, or cursing (which is not really swearing at all, rather a mere profanation of the divine name),³ but oaths as such (non iurare omnino). However, the prohibition contained in our Lord’s utterance and in that of St. James is plainly not absolute. If it were, Sacred Scripture would contradict itself, for not only has God repeatedly guaranteed His veracity by an oath, but oaths were an acknowledged part of the legal system of the Old Testament.⁴ Christ acknowledged the adjuration addressed to Him by the high priest, for He replied to his query.⁵ St. Paul repeatedly calls God to witness in a most solemn manner to the truth and sincerity of his preaching,⁶ and in his Epistle to the Hebrews expressly declares that “an oath for confirmation is the end of all controversy.”⁷

³ Cfr. St. Jerome, In Evangelium Matth., l. I, c. 5: “The Jews are known always to have this very bad custom of swearing by the elements. . . . Consider that here the Saviour did not forbid swearing by God, but by heaven and earth and Jerusalem and your head.” (Migne, P. L., XXVI, 39).—Cfr. St. Thomas, Summa Theol., 2a 2ae, qu. 89, art. 2, ad 1.

⁴ Deut. VI, 13; Ps. CIX, 4; Luke I, 73.

⁵ Matt. XXVI, 63 sq.

⁶ Rom. I, 9; 2 Cor. I, 23; XI, 31; Gal. I, 20; Phil. I, 8.

⁷ Heb. VI, 16.

3. The apparent contradiction between the two series of texts which we have cited can be easily solved. Both our Lord and St. James state it as a moral principle that in the kingdom of God oaths are not necessary, since all men would be honest and veracious if they lived up to His teaching. The disciples are forbidden to swear because oaths are incompatible with the perfect constitution of Christian society. In matter of fact, however, men are not perfect. They lie, they mistrust and cheat one another in consequence of the Fall, and whenever important interests are at stake, demand that God be called as a witness, “to whose eyes all things are naked and open” and to whom all men are responsible.⁸ By being asked to swear, a man is reminded of Him who is the author and avenger of the law, and his sense of duty is thereby sharpened.

⁸ Heb. IV, 13; Gen. XXV, 33; Matt. XXVI, 63.

An oath, therefore, is the highest and securest guarantee of human veracity, but it is at the same time a necessary evil, the last resource of society in sustaining law and order. It is, as the Ro- man Catechism truly says, “a remedy of human frailty and a necessary means of proving the truth of what we advance,” and “has been instituted on account of human weakness and really proceeds from evil” (i. e., from the depravation of human nature), as “‘it indicates either the inconstancy of him by whom, or the contumacy of him for whom it is taken, because he cannot otherwise be induced to believe.”⁹

⁹ Cat. Rom., P. III, c. 3, qu. 7, 19.

If taken under the conditions set forth in our next section, an oath is good and lawful because it presupposes, both in him who demands and in him who takes it, belief in an omniscient, truthful, and just God, and in this sense may be regarded as a solemn profession of faith.¹⁰ This explains why the Church has condemned it as erroneous to deny the lawfulness of oaths.¹¹

¹⁰ Profession of Faith Prescribed to the Waldenses by Innocent III: “We do not condemn an oath; rather, we believe with a pure heart that it is lawful to swear with truth, judgment, and justice.” (Denz.-Bannwart, n. 425).—St. Augustine, De Serm. Dom. in Monte, l. I, c. 17, n. 51: “If you are compelled to swear, know that this comes from the necessity of the weakness of those whom you are persuading of something; and that weakness is certainly an evil. . . . Accordingly He did not say, ‘Whatsoever is more is an evil,’ but ‘is of evil.’ For you do no evil when you make good use of an oath, which, though not good, is nevertheless necessary, so that you may persuade another of what you usefully advise; but it is from the evil of him by whose weakness you are compelled to swear.” (Migne, P. L., XXXIV, 1255).—St. Thomas, Summa Theol., 2a 2ae, qu. 89, art. 2: “An oath in itself is lawful and honorable. This is plain from its origin and its end: from its origin, because an oath was introduced from faith, by which men believe that God possesses infallible truth and knowledge and providence concerning all things; from its end, because an oath is introduced to justify men and to end controversies, as is said in Heb. VI, 16. But an oath turns to evil for someone from the fact that he uses it badly, that is, without necessity and due caution. For he seems to have little reverence for God who introduces Him as witness for a slight cause, something he would not presume to do even concerning an honorable man. There is also imminent danger of perjury, because man easily offends in word (Ecclus. XXIII, 9, 12; Jas. III, 2).”—Cat. Rom., P. III, c. 3, qu. 6, 7, 15, 16,

¹¹ Errors of John Wyclif condemned by Martin V, n. 43; Questions to Be Proposed to Wyclifites and Hussites, n. 12 sq.; proposition of Quesnel condemned by Clement XI, n. 101: “Nothing is more opposed to the spirit of God and the teaching of Jesus Christ than to make oaths common in the Church, because this is to multiply occasions of perjury, to spread snares for the weak and simple, and to cause the name and truth of God sometimes to serve the counsel of the impious.”—Cfr. proposition of the Diocesan Synod of Pistoia condemned by Pius VI, n. 75 (Denzinger-Bannwart, n. 623, 662 sq., 1451, 1575).

5. Oaths being justified only as a necessary means of human intercourse, as an antidote to untruth and dishonesty, and as a corrective of the unreliability of human testimony, their very nature demands that they be administered only in important cases, such as legal proceedings and trials, that no individual take an oath except at the demand of legitimate authority, and that the occasions on which it is demanded be restricted as much as possible, in order that what is in itself a sacred function be not cheapened to the detriment of society and sink to the level of an empty ceremony.¹² The too frequent swearing of oaths diminishes their value and the respect in which they are held by the people.

¹² St. Thomas, Summa Theol., 2a 2ae, qu. 89, art. 5.—Cat. Rom., P. III, c. 3, qu. 19.—F. A. Göpfert, Der Eid, pp. 221 sqq.

An oath should be demanded only when it can be made with proper regard to truth and the reverence due to God. No man should be compelled to swear to the truth of a complicated or obscure statement.

It is entirely just and consistent to debar per- sons who are notoriously unreliable or immoral, such as profligates, drunkards, usurers, and those convicted of perjury, from taking oaths. But it would be unjust, on the other hand, to demand an oath of the members of religious sects who in good faith reject swearing as immoral. American legislation generally allows such persons to “affirm” the truth of their statements and accepts this affirmation in lieu of an oath. If they “affirm” what is false they are liable to be prosecuted for perjury.

It goes without saying that atheists are incapable of taking an oath; to admit or, a fortiori, to compel them to take an oath would be contrary to the very nature of the oath as a religious act.¹³

¹³ Wisd. XIV, 28.—Göpfert, Der Eid, pp. 158 sqq.

READINGS.—St. Thomas, Summa Theol., 2a 2ae, qu. 89, art. 2.—V. Cathrein, S.J., Moralphilosophie, 4th ed., Vol. I, pp. 39 sqq.—E. Müller, Theol. Mor., Vol. II, 5th ed., pp. 195 sqq.—J. B. Ferreres, S.J., Comp. Theol. Mor., Vol. I, 9th ed., pp. 265 sqq.—H. Noldin, S.J., Summa Theol. Mor., Vol. II, 11th ed., pp. 254 sqq.—E. Hubrich, Konfessioneller Eid oder religionslose Beteuerung, Leipsic 1900.—N. Cecchini, Del Carattere Religioso del Giuramento e della Soppressione, Pistoia 1903.

439. Many have denied the lawfulness of an oath. Already the Pelagians and Messalians⁵¹⁹ seem to have denied the lawfulness of an oath. They were followed by the Waldenses,⁵²⁰ Beguines and Beghards, Fraticelli, Wycliffe,⁵²¹ the Hussites,⁵²² Anabaptists, Mennonites, Quakers,⁵²³ and others. Among philosophers, Kant and Fichte fought against the lawfulness of an oath. Against all these is set down:

Thesis. An oath clothed with the due conditions is lawful and licit.

⁵¹⁹ Cf. St. Augustine, Ep. 156 (al. 88); Sermon 180, c. 10, n. 11.

⁵²⁰ The following profession of faith was prescribed to the Waldenses: "We do not condemn an oath; indeed, we believe with a pure heart that it is lawful to swear with truth and judgment and justice" (Denz., n. 425; cf. also n. 487).

⁵²¹ Cf. proposition 43 condemned by the Council of Constance (Denz., n. 623).

⁵²² Cf. "Questions to Be Proposed to Wycliffites and Hussites," nn. 12-14 (Denz., nn. 662-664).

⁵²³ Cf. concerning all these errors Göpfert, Der Eid, 112ff. Since the Mennonites so abhor the taking of an oath, the civil laws of Germany have permitted them to employ other formulas confirming the truth to be spoken in place of an oath. Cf. Z.P.O. § 484.

440. Proof 1. From Sacred Scripture, which often acknowledges the lawfulness of an oath, e.g.: "Thou shalt fear the Lord thy God and shalt serve Him alone, and shalt swear by His name."⁵²⁴ St. Paul himself swore several times: "For God is my witness, whom I serve in my spirit";⁵²⁵ "But I call God to witness."⁵²⁶ But if Christ⁵²⁷ and James seem to reprove every oath, they are to be understood concerning an unlawful oath, or one not clothed with the due conditions. For St. Paul certainly knew the words of Christ, and nevertheless he himself swore several times. St. Augustine⁵²⁸ writes excellently on this matter: "Because it is impious to say that Paul was guilty of violating the precept, especially in epistles composed and published for the spiritual life and salvation of peoples, it must be understood that the word 'altogether' was placed for this purpose: that, insofar as it lies in thee, thou shouldst not seek, love, or desire an oath as though it were a good with some delight; ... namely, lest by swearing one come to readiness in swearing, and from readiness to habit, and from habit fall into perjury."

Proof 2. From the practice and doctrine of the Church. No one denies that the oath has always been employed in the Church as well as in the civil commonwealth. The doctrine of the Church on this matter is found in several decisions against the Waldenses, Wycliffites, Hussites, Quesnel, and the Synod of Pistoia, cited above in the preceding number.

Proof 3. From reason. An act whose origin and end are good is lawful in itself. But an oath is such. For an oath proceeds from faith in God as omniscient and as avenger of justice; but the end of an oath is to terminate controversies, obtain the full truth, and confirm promises. Therefore an oath clothed with the due conditions is something lawful and is an act of religion.⁵²⁹

But although an oath is lawful and licit in itself, nevertheless it is not to be sought for its own sake or employed too frequently, since otherwise abuses easily creep in.⁵³⁰ Because of these abuses, certain Holy Fathers spoke more severely concerning the oath, especially St. John Chrysostom and St. Jerome.⁵³¹ Therefore it is also said in Sacred Scripture: "Let not thy mouth be accustomed to swearing; for in it there are many falls.... A man that sweareth much shall be filled with iniquity, and a scourge shall not depart from his house. And if he make it void, his sin shall be upon him; and if he dissemble it, he offendeth double; and if he swear in vain, he shall not be justified."⁵³² The intrinsic reason is that an oath is, as it were, a medicine against the defect of human veracity and credibility. For if every man were always truthful, so that full faith could be given to his assertions, an oath would already be superfluous. Moreover, an oath can easily introduce a danger of sinning, since all the conditions required for its lawfulness are often absent. Therefore it is clear that an oath is not to be sought for its own sake, just as a man does not seek medicine except in a case of necessity.

Conditions required for a valid and lawful oath.

For a valid oath two conditions are required, namely: 1. the intention of swearing; and 2. an oath-formula. For a lawful oath, moreover, three conditions are required, namely: 1. truth; 2. justice; 3. judgment.

⁵²⁴ Deut. 6:13.

⁵²⁵ Rom. 1:9.

⁵²⁶ 2 Cor. 1:23; cf. also Phil. 1:8; Heb. 6:13-18.

⁵²⁷ "You have heard that it was said to them of old: Thou shalt not forswear thyself, but thou shalt perform thy oaths to the Lord. But I say to you not to swear at all.... But let your speech be yea, yea; no, no; and that which is over and above these is of evil" (Matt. 5:33ff., 37). St. James teaches the same: "But above all things, my brethren, swear not, neither by heaven, nor by the earth, nor by any other oath whatsoever. But let your speech be: yea, yea; no, no; that you fall not under judgment" (James 5:12).

⁵²⁸ De mendacio c. 15, n. 28 (Migne, Patr. lat. 40, 507).

⁵²⁹ Cf. S. theol. 2, 2, q. 89, a. 2.

⁵³⁰ Cf. ib., a. 5.

⁵³¹ There is no space to explain the texts of the Holy Fathers who apparently rejected the oath; for it is certain that the same Holy Fathers sometimes themselves declared an oath lawful. See Billuart, De relig. diss. 5, a. 3.

⁵³² Ecclus. 23:9, 12ff.

441. A. Conditions required for a valid oath:

1. An internal intention of swearing (whether actual or at least virtual) is altogether necessary for the validity of an oath; therefore, the external and material pronouncement alone of an oath-formula is not a true but a feigned oath. A feigned oath, however, seems to be a grave sin⁵³³ (at least if it is done freely and deliberately), since it is a grave injury inflicted upon God, who is dishonored by a deceitful invocation and is induced to deceive those hearing the oath. Hence proposition 25 was condemned by Innocent XI: "With a cause it is lawful to swear without the intention of swearing, whether the matter is light or grave."⁵³⁴ Hence those who freely take the oath-formula in a tribunal but inwardly withhold the intention of swearing do not escape the penalties of perjury either before God or before men. For a true and sufficient intention of swearing, it is required that the one swearing know what an oath is and that he have sufficient deliberation both concerning the act itself of swearing and concerning the matter of the oath. Because of a defect of a true intention of swearing, very many confirmatory formulas customarily used in human conversations are not true oaths; e.g., I assert this by my faith, by my honor, by my conscience; these things are as true as the light of the sun, as the existence of God; may the devil seize me if this is false, etc. Certainly these and similar formulas of speech signify that the speaker intends a great confirmation of his assertion, but it is by no means certain whether he really wills to invoke God as witness. The faithful are to be admonished to abstain from locutions of this kind as vain and indeed often sinful. "Let your speech be: yea, yea; no, no"; thus the Lord admonishes. In the external forum a true intention of swearing is always presumed when a true oath-formula has been pronounced.

⁵³³ If certain authors call a freely made feigned oath a venial sin or even no sin, they either teach falsely or take a feigned oath in the broader sense, insofar as it is a mere vain assumption of the name of God.

⁵³⁴ Denz., n. 1175.

442. 2. An oath-formula is required for the validity of an oath, because it must be an external sign for confirming the assertion made. This formula necessarily contains an explicit or at least implicit invocation of God, since the invocation of God as witness to the truth pertains to the essence of an oath. In ecclesiastical law the oath-formula customarily employed is: "So may God help me and these holy Gospels of God." In civil laws also, determinate formulas are customarily prescribed; if neither in themselves nor from the intention of the legislator they contain an invocation of God, they are not true religious oaths.⁵³⁵ In private oaths no determinate formula is required, but it suffices that someone intend by signs or words to invoke the divine name in testimony to the truth; indeed, an oath could be made to God Himself by an internal act, e.g., someone, in order that he may will firmly to avoid some occasion of sin, internally invokes God as witness.

⁵³⁵ Thus, e.g., the formula employed by the Mennonites, "I swear by the truthfulness of a man," is not a religious oath.

443. Scholion. On rightly understanding oath-formulas. Authors customarily weave here a rather long list of formulas of explicit or implicit oaths; likewise, they present several ambiguous formulas, or formulas certainly containing no oath. These seem to be of little utility, both because the validity of an oath, although not solely, nevertheless principally, depends upon the intention of the speaker, and because in diverse regions these formulas are understood differently. Let the following be noted briefly:

a) Formulas of speech in which God is explicitly or implicitly invoked as witness to the truth are true oaths, objectively speaking; e.g., "May God be my witness"; "I swear by God, by Christ"; "I swear by the Blessed Virgin, by the Cross, by the Gospels, by my soul," etc. But subjectively speaking, these or similar formulas of speech are sometimes to be regarded as a true oath neither from the intention of the speaker, who pronounces them without any serious deliberation and from inveterate habit, nor from their understanding by the hearers. For if someone confirms almost every assertion of his by exclaiming, "It is so, by God!"⁵³⁶ this manner of speaking is certainly to be reproved seriously as an intolerable abuse of the name of God; but neither the speaker himself nor the hearers think that every assertion thus confirmed is an oath.

b) Formulas in which God is neither explicitly nor implicitly invoked as witness are not an oath. Hence, if someone should say, "By my conscience, by my honor"; or if a priest should say, "By my consecration"; or if a prince should confirm his word, "By my royal honor," he does not indeed make a religious oath; nevertheless, these or similar formulas of speech are customarily regarded as such great confirmations of truth that their violation is considered truly base and scandalous.

c) Formulas by which the truth of an assertion is compared with truths of faith are not themselves an oath either. Hence the formulas, "This is as true as God exists; as Christ is in the venerable Sacrament; I am as innocent as the Blessed Virgin," etc., do not contain an oath, since they are not invocations of God's testimony; nor are they blasphemies, since the speaker is not accustomed to intend that his assertion have the same certainty as the truth of faith stated.⁵³⁷ But it is clear of itself that locutions of this kind are to be avoided altogether.

⁵³⁶ "By God, that is true!"

⁵³⁷ Cf. St. Alphonsus, Theol. mor. l. 3, n. 137.

444. B. Conditions required for a lawful oath.

For a lawful oath three conditions are required, already enumerated above, which are customarily called the companions of an oath,⁵³⁸ and which are already indicated by Jeremiah: "Thou shalt swear: The Lord liveth, in truth and in judgment and in justice."⁵³⁹ If even one of these conditions is absent, an oath lacks due reverence toward God and consequently is unlawful.

1. The truth of an oath does not signify the objective truth of the assertion made, but the veracity of the speaker, who does not speak contrary to his mind, or who does not tell a moral lie. This truth, therefore, presupposes a firm will to speak the truth (in an assertory oath) or to fulfill what is promised (in a promissory oath). Truth is the principal companion of an oath; if it is absent, there is the very grave sin of perjury, concerning which the discourse will return below in n. 456ff. But it is required not only that the one swearing avoid every moral lie, but also that he have moral certainty concerning the things asserted. Hence it is not lawful to swear either with doubtful truth or with merely probable truth. Likewise, it is never lawful to swear with a purely mental restriction. Thus holds the most common opinion, which is corroborated by the condemnation of propositions 26 and 28 pronounced by Innocent XI.⁵⁴⁰ But to swear with a broadly mental restriction is not lawful except for a grave cause; namely, in the case in which no other means is at hand to defend oneself or others against an unjust aggression, an unjust manner of questioning, or another grave evil. Thus a confessor who is unjustly compelled to give sworn testimony concerning things which he learned under the seal of confession can, and indeed must, swear with a mental restriction.

It is asked how great a sin it is to swear without sufficient cause with a broadly mental restriction. Many authors teach that such an oath is a mortal sin, since it is a grave irreverence against God to employ the invocation of His name to deceive others. St. Alphonsus⁵⁴¹ admits this doctrine concerning an oath in a trial or in contracts, but thinks it more probable that it is only a light sin if someone without sufficient reason employs a broadly mental restriction in other private oaths, because truth is not absent in such an oath, since the words pronounced can easily be understood in a right sense; nor is justice absent, because the questioner has no right, as is supposed, to a simple answer without restriction. Therefore only the third companion of an oath, namely judgment or discretion, is violated, and its violation is only a light sin. Although these things are true, nevertheless in practice this case seems scarcely possible. For it has already been prohibited that anyone swear without necessity or a grave reason. Therefore it is prohibited much more severely that anyone swear without necessity with a mental restriction.

⁵³⁸ Eidesgefährten [companions of an oath].

⁵³⁹ Jer. 4:2. Cf. also S. theol. 2, 2, q. 89, a. 3.

⁵⁴⁰ Cf. what was said above in n. 171 concerning mental restriction.

⁵⁴¹ St. Alphonsus, Theol. mor. l. 3, n. 151.

445. 2. Justice as the second companion is required in both an assertory and a promissory oath; it consists in this, that the one swearing neither asserts nor promises anything that is unlawful.

In an assertory oath, justice requires that no one unduly injure the reputation of another, e.g., by manifesting without sufficient cause the occult crime of another; that no one injure his neighbor in fortune; and that no one boast of a crime he himself has committed. A violation of justice in an assertory oath is a sin whose gravity depends a) upon the gravity of the injustice committed, and b) upon the intention of the one swearing. Hence it seems to be a mortal sin if someone, e.g., uses an oath as an instrument for proving a grave detraction,⁵⁴² because one who thus invokes God as witness represents Him, as it were, as an assistant in his crime. Almost the same seems to be said (although certain persons, e.g., Göpfert, contradict it) if someone for the sake of boasting confirms by an oath a narrative of his own grave sins. Nevertheless, in practice one must first see whether a true oath was present in these locutions; for often neither does the locution itself contain an invocation of the name of God, nor does the speaker have the intention of invoking God as witness to his sin.

In a promissory oath, justice requires that the one swearing promise nothing evil. Hence he who swears that he will perpetrate some grave crime (e.g., adultery, homicide, etc.) certainly commits a twofold grave sin: one sin offends the virtue which he intends to violate; the other sin is a grave violation of the virtue of religion, because the one swearing invokes God, almost mockingly, as witness that he wills to offend Him gravely. Thus all teach. But if the oath concerns the doing of a slightly evil thing, e.g., concerning a lie or a slight deception, certain grave authors, such as Dominic Soto,⁵⁴³ Cajetan,⁵⁴⁴ Sylvius,⁵⁴⁵ Busenbaum,⁵⁴⁶ Noldin,⁵⁴⁷ etc., judge that it is only a venial sin, because it is only a slight irreverence toward God. Other authors, however, such as St. Alphonsus,⁵⁴⁸ Billuart,⁵⁴⁹ Tanquerey,⁵⁵⁰ Göpfert,⁵⁵¹ etc., think that in this case also a grave sin is committed, because it seems to be a grave injury inflicted upon God to invoke Him as witness and, as it were, patron of even venial iniquity. For it seems to be contempt and mockery of God (who abhors all sins, even light ones) if a man, willing to commit a light sin, confirms his depraved intention by invoking divine testimony.

You resolve: From what has been said follows the solution of the following cases: 1. A certain Freemason swears that he will persecute the Church. There are certainly two mortal sins, namely, the persecution of the Church and a sacrilegious oath. 2. Someone swears that he will tell a jocose lie. There are two sins, namely, the light sin of a jocose lie and the perhaps grave sin of a sacrilegious oath. Rarely, however, do confirmatory formulas concerning a future venial sin to be committed have the character of a true oath, because of a defect of intention both in the one who speaks and in those who hear the speaker. Hence the first opinion, although considered theoretically it is less true, nevertheless can be held in practice.

Theologians commonly teach that it is only a light sin if someone swears to omit some good act which is counseled but not commanded, e.g., not to enter religion, not to give alms outside a case of necessity. Concerning this case the Angelic Doctor⁵⁵² says: "But if someone swears that he will not do some better good which nevertheless he is not bound to do, he sins indeed by swearing, insofar as he places an obstacle to the Holy Ghost, who is the inspirer of a good resolution; nevertheless, he does not sin by keeping the oath, but does much better if he does not keep it."

⁵⁴² Cf. St. Alphonsus, Theol. mor. l. 3, n. 146.

⁵⁴³ De iure et iust. l. 8, q. 2, a. 3, concl. 5.

⁵⁴⁴ Commentary on 2, 2, q. 89, a. 7.

⁵⁴⁵ Commentary on the same place.

⁵⁴⁶ In St. Alphonsus, l.c., n. 146.

⁵⁴⁷ De praeceptis, n. 255.

⁵⁴⁸ L.c.

⁵⁴⁹ De relig. diss. 5, a. 4.

⁵⁵⁰ De virt. relig. n. 951.

⁵⁵¹ Moraltheol. I, 355.

⁵⁵² S. theol. 2, 2, q. 89, a. 7 ad 2.

446. 3. Judgment (Besonnenheit, deliberateness) as the third companion of an oath requires due discretion, so that there be a) a just cause for swearing; b) due reverence in the act itself of swearing. A defect of this companion ordinarily is only a venial sin, provided, however, that the other two companions of an oath are present.

The reason is that the whole malice of a defect of judgment consists in this, that divine testimony is invoked vainly and superfluously, or not sufficiently reverently; this of itself does not seem to exceed venial guilt.⁵⁵³ Therefore those sin of themselves only venially who swear frequently without necessity, who swear jocularly, or who swear with insufficient reverence. But accidentally a defect of judgment in an oath can be a grave sin, namely, if grave scandal or a proximate danger of sinning against the truth or justice of the oath arises from it.⁵⁵⁴ Since a defect of judgment is so often present in oaths and introduces so many dangers of sin, Christ, St. James, St. John Chrysostom, and St. Jerome commended not swearing at all.⁵⁵⁵

⁵⁵³ Cf. Billuart, De relig. diss. 5, a. 4.

⁵⁵⁴ Fahrlässiger Meineid [negligent perjury].

⁵⁵⁵ Cf. the texts cited above in n. 440, and Göpfert, Der Eid, 61ff.

447. Scholion. Who can swear. By natural law every rational creature using reason, whether angel or man, whether having reached puberty or not, and even Christ Himself as man, can swear. The reason is that all creatures can confirm their statements by invoking divine testimony. If God Himself is at times introduced in Sacred Scripture as swearing, this is not an oath properly so called, because no one can invoke himself as witness to the truth; and especially it is not done as though the divine words needed confirmation, but such oaths show the immutability of God.⁵⁵⁶

By ecclesiastical law, several persons are not admitted to a solemn oath, e.g., those who have not reached puberty, infamous persons, and those who have already been convicted of perjury.⁵⁵⁷ Clerics ought not swear in a lay tribunal unless the prior permission of the bishop or legitimate prelate has been obtained.⁵⁵⁸ Priests, by reason of their dignity, ought not swear even in an ecclesiastical trial except for a grave cause, because to doubt their veracity is to derogate from their state.⁵⁵⁹

By civil laws, those who have not yet completed sixteen years are not customarily admitted to a judicial oath.⁵⁶⁰ Likewise, several others are excluded. Others, on the contrary, can refuse an oath. Concerning all these things, as pertaining solely to ecclesiastical or civil law, there is no space to treat more extensively here.

⁵⁵⁶ S. theol. 2, 2, q. 89, a. 10 ad 4.

⁵⁵⁷ Code of Canon Law, c. 1757.

⁵⁵⁸ Holy Office, decree of 23 Jan. 1886, and Code of Canon Law, c. 120.

⁵⁵⁹ S. theol., l.c., a. 10.

⁵⁶⁰ Cf. German Code of Civil Procedure, § 435, and Code of Criminal Procedure, § 56.

VII. Notions and principles concerning the morality of an oath. - An oath is the invocation of the divine name in testimony of truth, whether this is done directly, by immediately invoking God, or indirectly by means of creatures considered in relation to God (for example by faith, the cross, the Gospel, etc.); whether God is invoked as witness for manifesting truth (a contestatory or invocatory oath), or also as judge for punishing falsity (an execratory oath), as in the very well-known oath: so I swear, so may God help me.

On the part of matter, an oath can be merely assertory if only an affirmation is stated, or also promissory if a promise is also affirmed.

Now:

1. Three conditions are required for the liceity of an oath:

a) Truth, which excludes not material error but lying, so that the assertion is conformed to the actual mind of the one swearing, and the promise is also made with the present intention of fulfilling it.

b) Justice or honesty, so that the assertion made under oath is lawful, or also the thing promised itself.

c) Judgment or discretion, so that the oath is not made vainly and lightly but on account of a grave motive, and moreover the thing promised is in the power of the one swearing.

2. A fictitious oath without the intention of swearing, the first two conditions being verified, is reduced to an oath without judgment, as the expression usual among us: by God.

3. If some condition is lacking, to swear is a sin; and indeed:

a) A false oath, without truth, is mortal sin from its whole genus, because it is grave direct irreverence against God, who is supposed either not to know something or to be able to testify to falsity; this is perjury strictly so called.

b) An iniquitous oath, without justice, if it is promissory, is mortal sin, because it makes God the patron of sin; if it is merely assertory, it is of itself venial, unless it is directly used as a means of sinning, for example to affirm impure love in order to seduce a girl, because this is to make God a cooperator in sin.

c) An incautious oath, without judgment, is of itself venial, and is not mortal except by reason of scandal or danger.

VIII. Observations. - 1. One who accuses himself of oaths is to be questioned concerning what words he used, especially if he is unlearned. For often they say that they have sworn when they have simply affirmed something more firmly without any intention of invoking God as witness, for example by saying: God knows; God sees my conscience; I speak before God; it is as true as I sit, as the sun shines, as God, as the Gospel; I swear; I expose my head, may my ears be cut off if it is not so; indeed by my soul (mijn ziel), because ordinarily they do not regard the special relation between the soul and God. All these things of themselves are not oaths; unless nevertheless someone wished to invoke God as witness or avenger.

2. In this matter, the formulas and common estimation must be attended to most of all, for there are usual formulas which are not oath-formulas, and, on the contrary, there are truly oath-formulas which by common estimation are not such.

3. Since the whole matter depends upon the intention of the one swearing, the confessor a) should question him clearly, not indeed: whether he wished to swear (jurer, zweren), but more distinctly: whether he wished to offer an oath (faire serment, zijnen eed doen); b) should teach that for an oath there is required the intention of invoking God as witness; c) should turn him away from using formulas even doubtful and uttered without the intention of swearing, on account of irreverence toward God and the danger of scandal and deception.

S. Th. II-II, q. 89, a. 2, 3, 5, 7, 10.

749. Thesis. An oath according to itself is licit, under the due conditions. - It is of faith from Lateran Council IV, c. 3, against the Waldensians, and from the Council of Constance, against Wyclif, sess. 8, prop. 43 and a. 12.

The Beguines and Beghards, Fraticelli, Hussites, Anabaptists, Mennonites, and Quakers also denied the thesis.

The first part is proved: a) From the origin and end of an oath. From origin, because it has been introduced from faith by which men believe God to have infinite truth and universal knowledge and providence; from end, because it is introduced for justifying men and for ending controversies (Hebr. VI, 16), and because it is an efficacious means for obtaining the necessary security in human affairs, especially in contracts and judgments.

b) From many places both of the Old and the New Testament (Gen. XXII; Deut. VI, 13; X, 20; Ps. XIV, 4; LXII, 12; CIV, 9; CIX, 4; Eccli. XLIV; Is. XLV, 23; LXV, 15; Jer. IV, 2; Rom. I, 9; Phil. I, 8; II Cor. I, 23; Gal. I, 20; Hebr. VI), although Scripture proscribes its abuse, for example, in ordinary conversation (Exod. XX, 7; Lev. XIX, 12; Eccli. XXIII, 9-14; Mt. V, 34 sq.).

c) From the constant practice both of the faithful and of the Church, even in the earlier centuries (a. 2).

The second part is proved: An oath is not good through itself, but as a means to another thing; therefore it is not licit except under due conditions. For that which is sought only as a remedy for helping a defect is not good through itself, as is clear concerning medicine; but an oath is sought only for helping a defect, namely, that one man distrusts another; therefore an oath is not good through itself, nor licit except in necessity, but under due conditions (a. 2 and 5).

750. Three conditions are necessary for the liceity of an oath: judgment, truth, and justice, as Jeremiah IV, 2 indicates: "And you shall swear: The Lord lives, in truth and in judgment and in justice," which St. Jerome calls the companions of an oath (can. 1316).

For the good use of an oath two things are required: 1. that someone swear not lightly, but from a necessary cause and discreetly, namely, judgment of discretion on the part of the one swearing; 2. that the thing which is confirmed by oath be neither false nor illicit, namely, truth and justice on the part of the thing sworn. An incautious oath lacks judgment, a lying oath or perjury lacks truth, an iniquitous or illicit oath lacks justice (a. 3).

751. Judgment of discretion signifies a sufficient cause for swearing. For it is against the reverence due to the divine majesty to invoke it as witness of a thing of no or little moment (a. 2); which inordination nevertheless is of itself venial. In an assertory oath, a sufficient cause is a true utility for an honest end of sufficiently great moment, such as the public good, the peace of the family, security in a contract, one's own or another's reputation (condemned prop. Quesnel 101; Pistoia 73): in a promissory oath, it is required besides that the thing be in the power of the one swearing (a. 7).

752. Truth essentially requires conformity of the statement, not indeed with the thing sworn (material and objective truth), but with the mind of the one swearing (formal truth). For it is of itself a very grave irreverence toward God, infinite truth, to invoke Him as witness of falsehood or even as patron.

In an assertory oath there is only the truth of the assertion concerning the present, or the conformity of the statement with knowledge of the fact concerning which one swears, whence the certain is to be sworn as certain, the doubtful as doubtful, the probable as probable; in a promissory oath there is conformity of the statement with the present intention of doing that which is promised, and besides another truth is required, namely, conformity of the deed with the present promise, or truth of execution in the future (a. 7 and ad 1).

Therefore truth excludes a lie, but not error: thus he swears in truth who swears to something false which he prudently judges to be true; on the contrary, he commits perjury who swears what he thinks is false, although on the part of the thing it is true. Therefore in order that something be sworn as certain, practical and prudential certitude is required, or moral certitude improperly so called, which excludes every prudent doubt, greater however than for simply affirming; but for swearing judicially, experiential knowledge is required, because it is demanded by law.

753. Justice here signifies honesty. It requires 1. in an assertory oath, not indeed that the thing asserted, but that its assertion be honest: attestation of a crime before a judge is licit; the disclosure of a secret, profession of heresy, boasting of a crime committed, detraction, confirmed under oath, are dishonest; 2. in a promissory oath, not only that the promise itself, but also that the action or omission promised, insofar as it is sworn, be honest. For it is irreverence toward God's sanctity to call Him into testimony for a purpose or assertion which He prohibits (a. 7 and ad 2); which irreverence is grave from its genus.

754. Whether to swear befits all? - In an oath two things must be considered: one on the part of God whose testimony is invoked, and as to this the greatest reverence is due to an oath, and therefore non-pubescent persons and perjurers or those who are in danger of perjury are not admitted to it;¹ the other on the part of man whose statement is confirmed by oath, which he does not need except if there is doubt concerning his truth: but this derogates from the dignity of a person, that there be doubt concerning the truth of those things which he says, and therefore it does not befit persons of great dignity to swear, except on account of great utility or necessity (a. 10). Whence the Church has permitted an oath more sparingly to priests and religious, and prohibits a cleric from swearing before a lay judge unless the permission of the Apostolic See or of the bishop has been obtained (can. 120).

¹ Cf. can. 1757; and Belgian Penal Code, a. 31-34; Code of Civil Procedure, a. 285.

I. Alphonso a Castro reviews several heretics, both ancient and recent, who condemned all oaths (Bk. VIII, s.v. Iuramentum). The ancient heretics who taught that any oath whatsoever is unlawful for Christians are the Albanenses, the Bagnolenses, or Baiolenses, the Cathari, and the Pelagians. The more recent are the Waldensians, the Pseudo-Apostles, and the Wycliffites. For among the forty-five propositions of John Wycliffe condemned in the Council of Constance (session 45, year 1418), this one is found, which stands in the order 43rd: "Oaths are unlawful, which are made to corroborate human contracts and civil commerce."

II. To establish this error of theirs, the aforesaid heretics produce several arguments, drawn both from Scripture and from reason. From Scripture, indeed, they cite Hosea 4: "Neither shall they swear: 'The Lord liveth'"; and that of Zechariah 5: "Every thief shall be judged... and every one that sweareth in like manner shall be judged." They also press several passages from the Gospel. First, they object that of Matthew 5: "You have heard that it was said to them of old: Thou shalt not forswear thyself, but thou shalt perform thy oaths to the Lord. But I say to you not to swear at all, neither by heaven, for it is the throne of God; nor by the earth, for it is his footstool; nor by Jerusalem, for it is the city of the great king; neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your speech be: yea, yea; no, no: and that which is over and above these, is of evil." In this text two things are prescribed. First, an oath is absolutely forbidden — for that particle "at all" seems to signify this. Then a formula for confirming our assertions is designated, in those words: "But let your speech be: yea, yea; no, no; and that which is over and above these, is of evil." James the Apostle likewise, in chapter 5, with such great emphasis, proscribes the oath, that these words which follow inhibit oaths still more forcefully: "That which is over and above these, is of evil": "But above all things, my brethren, swear not, neither by heaven, nor by the earth, nor by any other oath. But let your speech be: yea, yea; no, no: that you fall not under judgment." Three Fathers, too, not obscurely indicate that oaths were forbidden even to Christians. Tertullian, in his book On Idolatry, ch. 20, writes this: "I say nothing of perjury, since it is not even lawful to swear at all." Clement of Rome, or the author of the Apostolic Constitutions (Bk. VI, ch. 11): "Our Master commanded that we should not swear even by the true God, so that our word might be held firmer and more credible than an oath." Finally, this can be confirmed by reason. Since man, being of the lowest rank, cannot bring God forward as witness, especially to confirm human contracts, pacts, and business affairs. For the person of God is of the supreme order: therefore he cannot be invoked to confirm these inferior transactions, without a monstrous perversity of order.

III. It is a truth of faith that not every oath is forbidden, or unlawful, for Christians. St. Thomas (II-II, q. 89, art. 2) establishes this assertion both by the authority of Scripture, by reason, and by the examples of the Saints. That an oath is, by its own nature, honorable, he demonstrates from its origin and its end. From its origin, indeed, because an oath is introduced from the faith by which men believe God to have infallible truth, and universal knowledge and providence of all things. From its end, however, because an oath is brought in to justify men, and to end controversies. Then he shows that God himself commanded an oath — which he would never have done, if an oath were, by its own nature, unlawful. Now Deuteronomy 6 has this: "Thou shalt fear the Lord thy God, and shalt serve him only, and thou shalt swear by his name."

IV. Our assertion is confirmed by the examples of the Saints. The Apostle Paul called God to witness (Romans 1) in these words: "For God is my witness." He also employed an oath (2 Corinthians 1): "But I call God to witness upon my soul, that to spare you, I came not any more to Corinth." What he wrote to the Galatians, he confirmed by oath (ch. 1): "Now the things which I write to you, behold, before God, I lie not." What more? God himself confirmed by oath the promise made to Abraham: "By my own self have I sworn, saith the Lord, because thou hast done this thing," etc. Finally, Christ, the necessary conditions being observed, always approved oaths, and frequently exacted them, whether to abjure heresy, or to purge oneself of crimes, or to end lawsuits, or to confirm obedience — as Paul attests (Hebrews 6), that an oath is the end of all controversy. To the testimonies of Sacred Scripture is added the custom of the Church, which approves the use of oaths, and confirms them, as is held in the titles on heretics, and on the law of oaths, which are more fully declared in the Councils of Ephesus, of Constantinople, and in the title on canonical purgation.

V. To the arguments of the heretics, setting aside the various responses of Jerome, Bernard, and other Fathers, we set forth those which Augustine and Thomas present — for their responses are approved by almost all. Augustine, then (On the Lord's Sermon on the Mount, Bk. I, ch. 17), expounds the described text of Matthew, and interprets it in these words: "It is thus, then, understood that the Lord commanded that one should not swear, not because swearing is good, but lest anyone, through the assiduity of swearing, slide by custom into perjury. Wherefore he who understands that an oath is to be used not as a good, but as a necessity, should restrain himself as much as he can, so as not to use it except from necessity... To this, then, pertains what is said: 'But let your speech be: yea, yea; no, no.' This is good, and to be sought. But that which is more than this, is of evil — that is, if he is compelled to swear, let him know that this comes from the necessity of the weakness of those to whom he persuades something, which weakness is certainly an evil; from which we daily pray to be delivered, when we say: 'Deliver us from evil.' He did not say, then, 'that which is more is evil'... but 'of the evil,' that is, of that man's weakness, on whose account you are compelled to swear." Augustine gives this same response elsewhere (Bk. IV, Against Lying, ch. 15), where he confirms it by the example of Paul: "The Apostle himself swore in his Epistles, and shows that it is a more cautious course not to be found swearing, except in writing, where one considers with care what is said — lest, from the ease of it, one falls into a habit, and thence, from habit, into perjury. And therefore it is not found that he swore verbally, where a precipitate tongue might be considered." St. Thomas, in the place cited, adopts these two responses of Augustine, and by them resolves the first and second arguments. And by these, too, the response to James's authority is made clear, who speaks in the same sense as Matthew.

VI. To the testimonies of the Fathers we say that they disapproved the easy use of swearing, but by no means denied that it was necessary. It is indeed true that they did not assign this exception, since it was by no means necessary for them to do so — just as Christ did not declare this exception either, as Sotus notes (On Justice and Law, Bk. VIII, art. 2). For since they were then reprehending men inclined, through habit, toward swearing, it did not at all pertain to their purpose to teach them that it was sometimes lawful to swear — since this was already manifest through the very persons to whom they spoke. This same thing happens to us commonly: when we reprove some vice, we do not always explain the opposite virtue. Augustine's teaching confirms this interpretation, which he presents not as merely probable, or recently discovered, but as common, and subject to no controversy. As to the argument from reason, it is said that man cannot induce God, by his own voice or sign, to show the truth; nor does this truth depend on the one to whom the oath is sworn; but man only calls God to witness, so that what he asserts may merit greater authority and credit among other men, and become more credible — which suffices for the utility of the oath. This is well shown by the deed of St. Basilides the Martyr, of whom Ambrose writes this: "When Basilides was pressed by his fellow-soldiers to swear by the fates" — since he was a Christian... , he judged it wrong for himself to do this, and openly professed it." Eusebius likewise objects (Bk. VI, Ecclesiastical History, ch. 5), affirming that it is unlawful for all... But the common response is that this soldier, recently made a Christian, was ignorant of the rules which Christians observed in the use of oaths. And since he observed that Christians abstained from oaths with the utmost caution, because they swore only under urgent necessity, he falsely judged that an oath was not permitted to Christians at all. Besides which, he was induced to swear not by a judge, but by his fellow-soldiers, and perhaps by their false deities: for this reason he refused to swear.

VII. An oath, then, is lawful for Christians, the conditions being observed which we shall explain below. Indeed, St. Thomas, after having demonstrated in article 1, against the heretics, that an oath is lawful and honorable, shows in article 4 that it is an act of the virtue of religion, or of latria — since one who swears, invoking God as witness, confesses the faithfulness of God, in that he acknowledges God as the first truth, and the founder and provider of all things. Just as, then, prayer, whereby God is invoked as helper, is an act of religion, so too an oath, whereby he is invoked as witness of the truth, is an act of religion: in both cases, the Angelic Doctor concludes, it is manifest that reverence is shown to God. Whence it is clear that an oath is an act of religion, or of latria.

I. From Chapter II of this Dissertation it has been demonstrated against the heretics that an oath is an honorable act, and lawful, indeed an act of virtue — namely, of religion, or of latria — provided it is attended by the necessary conditions. In this chapter we undertake to explain these conditions, which ought to accompany an oath. But, before we examine each singly, it must be noted, from St. Thomas, that an oath is not absolutely to be sought after, and frequently employed. For, among those goods which are to be sought only when necessity presses, one may reckon that which is medicine — a good thing, given the illness which it meets. Thus an oath has been instituted to provide for weakness — namely, of the incredulous man. "Just as medicine (says the Angelic Doctor, q. 89, art. 5, ad 3) is useful for health, but the more virtuous it is, the greater harm it induces, if not duly taken — so too an oath is indeed useful for confirmation by divine testimony; yet the more it is to be venerated, the more dangerous it is, unless duly employed."

II. Now, in order for an oath to be opportunely employed, three conditions must accompany it, as Jeremiah 4 has it: "Thou shalt swear: As the Lord liveth, in truth, and in judgment, and in justice." St. Thomas assigns the reason why these three conditions are required (loc. cit., art. 3, in the body): "An oath is not good, except for one who uses it well. For a good use of an oath, two things are required. The first is that one swear not lightly, but from a necessary cause, and discreetly, as regards that which is confirmed by the oath — namely, that it be neither false, nor anything unlawful; and as regards this, judgment is required. The second is required on the part of the swearer's discretion. First, one swears truly by an oath who confirms that which is true; but an oath lacking judgment is called rash. Second, one swears rightly by an oath who confirms by it what is lawful. As regards this, truth is required, whereby it is true, and not a lie; and justice, by which one confirms what is lawful."

From this angelic teaching, the sense of the aforesaid conditions plainly shines forth.

III. In every oath, then, truth is first necessary, in confirmation of which divine testimony is invoked. This truth, or certainty of the truth, can be considered both on the part of the thing sworn, and on the part of the swearer. On the part of the thing sworn, it is required that the thing sworn be true according to common understanding and custom. Thus one who swears that a student frequented the schools swears truly, even if he was sometimes absent — since this is commonly understood in this sense. Certainty on the part of the swearer consists in this: that a man confirm, by oath, a matter such as he holds, or believes, in his mind to be true. If he knows the matter to be certain, he cannot swear it as doubtful; and if he judges it to be doubtful, he cannot swear it as certain. In a promissory oath, a twofold truth is implied: one, of the intention now had of fulfilling what he promises; the other, future, or of the deed, in the execution of what is promised. But of this twofold truth, more below.

Second, justice is required for an oath: that truth is necessary for an oath which excludes from the matter to be confirmed anything unjust, or any dishonorable thing — that is, an unlawful, culpable saying or deed, whether contrary to justice, or to any other virtue. He is said to swear falsely who confirms, by oath, present or future matter, contrary to what he presently has in mind. He is said to swear unjustly and wickedly who is opposed to justice. The former is opposed to truth by oath; the latter, to justice.

Third, judgment is necessary, which is not taken for the exercise of justice, but for prudent consideration; and it consists in this: that a man, before he swears, maturely and seriously weigh the utility and necessity of swearing. For, just as prudence is the guide, or rule, of all the virtues, especially insofar as it directs the oath, this third condition is supremely necessary, so that the oath may be lawful, and an act of virtue.

The first two conditions, however, are required so that it may not be a sin. Under this "judgment," in a certain way, are contained all the other conditions. As to truth and justice, this is clear: for, just as this judgment prescribes that one ought to swear, having regard to the utility and necessity of the matters, so too it forbids swearing to something false, or vicious. Other conditions too — chiefly theological faith, whereby one believes that God knows all things, and devotion, whereby, on the part of the swearer, the reverence owed to God is shown — are, St. Thomas openly teaches, comprehended under "judgment" (loc. cit., art. 5, ad 2): "Devotion, and faith, and all such things as are required for the due manner of swearing, are understood as included in judgment."

St. Augustine speaks excellently of this "judgment" (Sermon 28, on the words of the Apostle, ch. 9): "As far as it depends on me, I do not wish to swear; but, when I see that I am not believed, and that it is not expedient that he does not believe, who does not believe him to whom I am a witness — this reason having been weighed, and this consideration balanced, I swear, compelled by great necessity, as it seems to me, saying, with great fear, in the presence of God, or, as Christ knows in my soul, or such things."

IV. The Angelic Doctor not only explains the three common conditions which ought to accompany any oath whatsoever, but furthermore pursues the occasions in which an oath is free of fault, indeed possesses the merit of virtue. He assigns six such cases. First, when an oath is a conclusion of peace. Second, the necessity of preserving one's own reputation. Third, as a pledge of fidelity to be maintained. Fourth, for rendering obedience to a superior. Fifth, when the necessity presses of securing a promised thing. Sixth, so that the truth, which it greatly matters be believed, may be rendered credible. Here are the words of the holy Doctor, in his Epistle to the Hebrews, ch. 6: "The causes, however, in which it is lawful to swear, are these. First, for the confirmation of peace, as Laban swore (Genesis 30). Second, for the preservation of one's reputation. Third, for keeping fidelity, as vassals swear to their lords. Fourth, for fulfilling obedience, if something honorable is commanded by a superior. Fifth, for effecting security. Sixth, for attesting truth." Thus swore the Apostle (Romans 1): "God is my witness."

VERY many heretics deny altogether that an Oath is licit. Among these are the Manichaeans, whom D. Bonav. reports here, and the Apostolici, according to D. Bernard homil. 66. in Cant. and the Cathari, by the testimony of Guido, and the Pauperes de Lugduno according to the same, and the Fraticelli, by the testimony of Turrecremata lib. 4. summae de Ecclesia part. 2. cap. 37. Vuiclephus error 43. from the condemned in the Council of Constance sess. 8. who said that one ought not to swear to confirm human contracts; so also the Anabaptists, according to Cochlaeus against the same, and Erasmus ad 5. Matthaei.

I ASSERT, however, that the Oath is licit.

It is PROVED from D. Bonav. first from 5. Matth. But thou shalt render to the Lord thy oaths. The same is had in Deuter. 6. Thou shalt fear the Lord thy God, and shalt swear by his name, and cap. 21. where the Magnates of the neighboring places, in which a man had been found slain, are commanded to purge themselves by oath, and Psalm. 62. All shall be praised who swear by him, and Heb. 6. where it is said: An oath is the end of all controversy, as S. Bonaventure rightly notes serm. 3. Decalogi, and loco cit. after D. Augustine serm. 28. de verbis Apostoli.

It is PROVED secondly from D. Bonaventure. That which has God and the Saints as exemplars is not sin: But the oath was instituted by God, and the Saints: Therefore. The minor is proved, Genes. 22. By myself I have sworn, saith the Lord. Psalm. 119. The Lord hath sworn. Heb. 6. He swore by himself. Besides, as often as in the old testament he said: I live, and in the new: Amen, amen, (which is frequent) God swore, as D. Jerome rightly notes also ad 16. Ezech. Chrysostomus homil. 11. in epistolam ad Heb. Oecumenius in cap. 3. ad Heb. and it is had cap. Etsi Christus, extra de iureiur.

SIMILARLY also the Saints swore: thus Abraham Genes. 21. Jacob and Laban Genes. 31. Moses and Jethro Exodi 2. David 1. Reg. 20. second, Reg. 1. the Apostle Rom. 1. second, Cor. 1. Philip. 1. and in other places, as S. Bonaventure reports serm. 3. Decal. and in 3. dist. 39. passim and in the Bibliis Pauperum, cap. 18. Therefore. It is the argument of D. Augustine loco cit. and lib. 19. cap. 23. contra Faustum, and of other Fathers.

It is PROVED thirdly. That by which honor is shown to God is licit: such is the oath: Therefore. The minor is proved by D. Bonaventure from the Gloss in 5. Matth. because while we bring God in as witness of the truth, we confess that God is the first infallible truth, on whom we lean, in whom we hope for the truth to be unfolded, whom we fear, whom we love, and therefore we remit ourselves wholly to him. These things Suarez pursues at length lib. 2. de religione, Tract. de iuramento, lib. 1. cap. 4. and 7.

It is PROVED fourthly from D. Bonaventure. That which has a holy object and end is licit; such is the oath, which has for object the Divine invocation, to unfold the truth, to promote good, to preserve fidelity, to promote peace, to curb malice, to settle controversies, duly to purge infamies, as is had in Heb. 6. Deuter. 21. cited above: Therefore. See D. Bonaventure.

D. Bonavent. also serm. 3. Decal. et loco cit. Gentil. On these arguments lean Suarez loco cit. Valencia 2. 2. disp. 6. quaest. 7. puncto 3. Castro lib. 8. contra haeres. V. Iuram. Azor Tom. 1. lib. 11. cap. 2.

You will object first Matth. 5. Christ says: But I say to you, not to swear at all.

D. Bonaventure answers ad primum, and serm. 3. in Decalogum, that Christ did not prohibit the oath universally, but only prohibited that we should swear too easily in every affair. For therefore he did not say: I say to you not to swear at all, which would render a universal negative: but he says: I say to you not to swear at all, that is, not always, and so easily. For a negation placed before the sign of universality is equivalent to a particular negative. Thus: Not every man runs, is a particular negative: But the negation placed after makes it universally true, as: Every man does not run. Azor receives this response Tom. 1. lib. 11. cap. 3. quaestio 5.

Valencia loco citato, after Gabriel in 3. dist. 39. quaest. 1. rejects this response, because the sentences of Sacred scripture are not to be measured by the rules of the Dialecticians, and it is certain that under the same form of speaking there stands in Scripture a universal prohibition, as Exodi 20. Thou shalt not make to thyself a graven thing, nor any likeness.

¶ But what harm does this acute observation of the Seraphic Doctor do, that these men should attempt by no reason to overturn it utterly? Moreover I show it solid: For often, and ever more often, Scripture is expounded by these rules, as is everywhere seen in the SS. PP., especially Augustine; for the rules of Dialectic were handed down to find the truth of propositions; and in this case the text was translated word for word from the Greek, which sounds altogether thus, as is read in the text. But we know that the Greeks use these Aristotelic rules. So also we very often see sacred scripture using figures and Tropes.

Indeed the Example brought forward by Valencia is for us: For there not all images are prohibited universally, for God himself commands the Cherubim to be woven, others to be sculpted; but only those to which the honor of latria is paid, or by which it is paid to other creatures, as Valencia himself confesses 2. 2. disp. 6. quaest. 11. puncto 6. col 1461. where he says this is the irrefragable sense of all Catholics. Wherefore that is a particular negative proposition.

Other responses therefore having been rejected, Valencia answers from D. Thom. art. 2. ad 1. and D. Augustine lib. 19. contra Faustum, cap. 23. and lib. de mendacio, cap. 15. that Christ the Lord prohibited the facility, and accordingly the temerity, in swearing, with which the Pharisees abounded. But that this was Christ's Scope he proves from the beginning of the sermon: Unless your justice abound more than that of the scribes, and Pharisees, you shall not enter into the kingdom of heaven.

Moreover, for this exposition he could bring forward also S. Bonaventure loco cit. ad secundum, and in corpore. But the reason which Valencia adds from his own store is a frivolous invention; for Christ sufficiently assigned the more abundant justice necessary in this respect, blunting their use of swearing by creatures, on this pretext, that swearing by them is not an oath. But that he rather prohibited too great facility in swearing, whence an oath could lack truth also through inconsideration; or prohibited that they should not swear in every light matter without necessity, as S. Bonaventure says in the former exposition, is not gathered even by a word. Add that in the former exposition of D. Bonaventure this second is contained, namely, that it is prohibited that at every third word, from any slight occasion and slight little cause, we precipitately and inconsiderately swear.

You will object secondly, Iacobi 5. But above all, my brethren, do not swear.

S. Bonaventure answers in corpore, and ad 2. from D. Augustine ad Publicolam, that it forbids the facility of the oath because of the danger of perjury from inconsideration of the truth. So Valencia also answers loco cit. The same response from D. Bonaventure ad secundum, he gives to the Fathers who frequently inveigh against swearers.

S. Bonaventure adds that the Divine James intends also to remove the excessive affection toward oaths; therefore he says: Do not, because of the danger which follows from the affection of frequenting the oath without the due conditions; for too great frequency is evil. From which, however, it does not follow that the oath is absolutely evil: As the habit of laughing and playing is evil; yet sometimes to play and laugh moderately is the virtue of Eutrapelia. Whence S. Bonaventure refutes that argument: Every act whose habit is evil, is itself evil; but the habit of swearing is evil: Therefore also the act simply. He adds therefore for this reason that the Oath is not among those goods to be sought for themselves, but that it is licit to use it in necessity alone, which he proves from D. Augustine de serm. Domini in monte, lib. 1. cap. 30. and it is reported, cap. Ita ergo, 22. quaest. 1. and D. Thom. art. 5. has the same.

You will object thirdly, that it is perverse to invoke God as witness of profane and human things as though it were licit.

S. Bonaventure answers serm. 3. Decal. from the Apostle Heb. 6. That this is judged right by God; for peace is a most weighty good, necessary unto salvation, but controversies having been settled, peace is preserved. Therefore the invocation of God is not ordered, as to the last end, to profane affairs, but the end of controversies is peace, which returns into God, and is terminated in him. In the same way answers Valencia loco cit. and Azor Tom. 1. lib. 11. cap. 3. quaestio 5. and Iurisconsult. leg. 1. ff. de Iureiurando.

It was the opinion of St. Jerome on Matthew 5 that it was forbidden by Christ to swear by creatures. Alphonsus de Castro followed him, V. Iuram. haeresi 1. and it seems Innocent III cap. etsi Christus, de Iureiurando.

Yet the true sentiment is that it is lawful to swear by creatures. So St. Bonaventure here, St. Thomas ad primum, whom all the others follow, as Azorius says Tom. 1. lib. 11. cap. 3. quaestio 5.

But Azorius notes, from St. Bonaventure in corpore, that one can swear by creatures in two ways; first by them as invoked as witnesses of truth, as if divine, in which manner the pagans swore AEdepol, Mehercule; and this contains blasphemy, evidently because that is ascribed to creatures which is proper to God, to be the infallible author of truth; and this is forbidden cap. Clericum, 22. quaest. 1. by the Fourth Council of Carthage et cap. si quis per creaturas.

In the other way one swears by creatures, not resting in them, but invoking God, who shines forth in creatures as the workman, as the author of all truth and goodness; in creatures also this is lawful, as I shall show below.

I ASSERT, that it is lawful to swear by creatures.

It is PROVED by St. Bonaventure first. Joseph Genes. 43. swore by the health of Pharaoh, and Paul prima Corinth. 11. by the glory of the Corinthians: Daily I die by your glory. So St. Augustine understands it serm. 28. de verbis Apostoli in Glossa ordinaria. Others however read: I die on account of, etc. But the Greek text has, Per. So St. Bonaventure also reads it in Bibliis pauperum, cap. 18.

It is PROVED secondly by St. Bonaventure, because an oath is commonly administered by the Church upon the Gospels; but the Gospel is a creature.

You will OBJECT first Matth. 5. Christ says: Swear not by heaven, because it is the throne of God: nor by the earth, because it is the footstool of his feet, etc. The Gloss says this is superstitious.

St. Bonaventure ANSWERS that an oath by creatures is forbidden in the first way, by attributing to them something Divine; but that to swear in the second way is lawful, with due moderation, as above.

You will OBJECT secondly. Pope Pius forbids swearing by a hair Dei 22. quaest. 1.

St. Bonaventure ANSWERS: he condemns those who ascribe members to God; and those who swear contumeliously by the members of Christ.

The habit of swearing is not in itself a sin distinct from the very acts of swearing that are frequent. For it is the very act frequently repeated, as Aristotle teaches in 2 Ethics; but the effect of the acts, which is a certain habit of swearing, resulting from frequently repeated acts, inclines to evil, and so far is vicious; nevertheless it cannot be a sin, which ought to be found in the acts. So Soto lib. 8. de Iustitia, quaest. 2. art. 3. concl. 7. Suarez lib. 3. cap. 6. Sanchez lib. 3. cap. 5. num. 4. Yet that habit of swearing can be a proximate occasion of mortal sins, and for that reason can place one in a state of mortal sin. The question, therefore, is when this happens.

¶ The first opinion is that any habit whatsoever of swearing, even if it is not one of lying under oath, makes one guilty of mortal sin. So Soto de cavendo iuramentorum abusu, cap. 11. Sayrus lib. 5. cap. 9. num. 8. where he says that such persons are not to be absolved unless they propose to root out the habit.

The second opinion is that a habit of swearing joined to a habit of lying without an oath places one in danger in this state, and so far is one mortally wounded. So Gregory of Valencia 2. 2. disp. 6. quaest. 7. puncto 3. Petrus Ledesma 2. Tomo summae, tract. 11. cap. 5. dub. 5. dicto 2.

The third opinion is that such a habit of swearing is [evil] when one swears with attention to the oath, but not to the truth or falsity of the thing sworn; but otherwise when one attends to neither, and the emission of the oath outruns the full attention of reason. So Azorius Tom. 1. lib. 11. cap. 3. quaestio 3. and Bassaeus V. Iuramentum 4.

The fourth opinion is that of Sanchez lib. 3. cap. 5. a num. 9. where he says five things. First, that a habit of swearing with due attention to the truth of the thing sworn does not place one in a state of mortal sin; and in this part he has as assertors Scotus 3. dist. 39. quaest. unic. art. 1. Gabriel quaest. 2. art. 1. notab. 2. Sayrus lib. 5. cap. 5. Medina lib. 1. summae, cap. 14. §. 4. Lopez p. p. Instruct. cap. 25. et cap. 42. SECOND, Suarez says that neither a habit of lying joined to a habit of swearing what is true is mortal. For this he also cites Suarez lo. co citato, num. 6.

THIRD, he says that a habit of swearing indifferently, whether what is true or what is false, is mortal. He also cites Suarez cap. 6. num. 6. et 8. Petrus Ledesm. 2. Tomo, tract. 11. cap. 5. dub. 4. Valentia loco cit. Vega loco citato.

FOURTH, he says that when there is a habit of swearing inattentively regarding the truth of the thing sworn, it is mortal. He also cites Aragon 2. 2. quaest. 89. art. 3. dub. ultimo, Suarez loco cit. num. 9. Petrus Ledesma cap. 5. dub. 4. Azorius Tom. 1. lib. 11. cap. 3. quaestio 3.

FIFTH, the same must be said when the habit is of swearing without attention, whether one swears or not, against the third opinion; and he also cites Suarez num. 8.

AS REGARDS St. Bonaventure, in the following assertions I shall state what he thought about this matter.