Section — Koch–Preuss
Section 4: Sins Committed in Connection with Oaths
Whenever any one of the conditions required for the lawfulness of an oath is wanting, he who swears it commits a sin.
If the condition lacking is truth, the sin committed is called perjury (periurium); if judgment, the sin is called unjustifiable swearing; if justice, we say that the vovens swears unjustly.
- PERJURY.—Perjury (periurium, peieratio, iuramentum falsum) may be defined as calling on God to witness the truth of an assertion which we know to be false, or in confirmation of a promise which we do not intend to keep.1
1 Peter Lombard, Sent., III, dist. 39, n. 1: “Perjury is a lie confirmed by an oath.”—Ibid., n. 2: “He also is believed to perjure himself who swears falsely with the will to deceive; and he who, thinking false what is true, swears; and he who, thinking true what is false, swears.” (Migne, P. L., CXCII, 835).—St. Thomas, Summa Theol., 2a 2ae, qu. 98, art. 1: “Moral acts receive their species from the end. Now the end of an oath is the confirmation of a human statement, to which confirmation falsity is opposed. For a statement is confirmed by showing that it is firmly true, which cannot occur concerning that which is false. Hence falsity directly destroys the end of an oath, and for this reason the perversity of an oath, which is called perjury, is specified chiefly by falsity. And therefore falsity belongs to the essence of perjury.”
a) The moral guilt of perjury is measured, not by the importance of the matter involved, i. e., the assertion or promise made under oath, but solely by the perjurer’s knowledge of its untruth. This applies to simple (periurium simplex) and also, a fortiori, to solemn perjury (periurium solemne), when the false oath is taken after due instruction and admonition and with the ceremonies prescribed by law.
Perjury is ex toto genere suo a grievous sin, being not merely a qualified lie, an attack upon the highest guaranty of veracity, and a criminal profanation of the name of God, but likewise a public scandal and a sin against religion,2 which even the civil law punishes severely.3 As a rule this sin involves a gross violation of justice against one’s neighbor and against society.
2 Zach. VIII, 17; Mal. III, 5; 1 Tim. I, 8–10.—Proposition condemned under Innocent XI, n. 24: “To call God as witness to a light lie is not so great an irreverence that He would or could condemn a man because of it.”—Ibid., n. 25: “With a cause it is lawful to swear without the intention of swearing, whether the matter is light or grave.” (Denzinger-Bannwart, n. 1174 sq.)—Cfr. the Bull “Inter cunctas,” of Pope Martin V, n. 14 (Denzinger-Bannwart, n. 664).—St. Thomas, Summa Theol., 2a 2ae, qu. 98, art. 2: “To swear is to invoke God as witness. But it pertains to irreverence toward God that someone invoke Him as witness to falsity, because by this he gives it to be understood either that God does not know the truth or that He is willing to testify to falsity. And therefore perjury is manifestly a sin contrary to religion, whose office it is to show reverence to God.”—Ibid., art. 3: “Whatever by its own nature pertains to contempt of God is a mortal sin. But perjury by its own nature implies contempt of God; for from this it has the character of guilt, because it pertains to irreverence toward God. Hence it is manifest that perjury by its own nature is a mortal sin.”
3 Cfr. F. Bittner, Lehrbuch der kath. Moraltheologie, pp. 376 sq.
All sins of perjury are of the same moral species as the various oaths themselves. This holds even of the so-called periurium exsecratorium, which involves cursing one’s neighbor, though we do not, of course, mean to deny that if the evil is wished seriously, it entails an additional sin against charity.4
4 H. Noldin, S.J., Summa Theol. Mor., Vol. II, p. 268.
The alarming increase of perjury in our time is no doubt largely attributable to the decline of religious faith and the growing carelessness in matters of morals. Another, minor cause is the unnecessary multiplication of oaths and the frivolous manner in which they are often administered by public officials. This abuse should be cured by the State, but the Church can aid powerfully by influencing the consciences of men. “We are forbidden to take the divine name in vain,” says the Catechism of the Council of Trent; “for he who is led to make oath, not by deliberation, but by rashness, evidently involves himself in grievous sin. That this is a most grievous crime, these very words declare: ‘Thou shalt not take the name of the Lord thy God in vain,’ words which, as if to assign the reason why this is so grievous an enormity, namely, because the majesty of Him is abased whom we profess to be our Lord and our God. By this commandment, therefore, it is forbidden that men swear falsely; for he who shrinks not from the enormity of calling God to witness falsehood, offers a signal injury to God, branding Him either with ignorance, as though the truth of anything could be hidden from Him, or at least with improbity and depravity, as though He would by testimony confirm falsehood.”5
In some dioceses perjury committed in a court of law is a reserved case in both the internal and the external forum. (Cfr. C. I. C., can. 2323.)
b) Akin to perjury is the wilful breaking of a valid oath or the intentional nonfulfilment of a promise given under oath (fractio iuramenti promissorii). The sinfulness of this act depends not only on the degree of malice inherent in the will, but likewise on the extent to which the oath is actually broken. To neglect to keep a promissory oath is, therefore, ex genere suo a grievous sin because the obligation imposed by such an oath is grievous. It permits, however, of parvitas materiae. “He who binds himself by an oath to the performance of something, not intending, however, to fulfil his promise, or having had the intention, really neglects its performance, is guilty of the same sin [as he who commits perjury ]; and this applies also to those who, having bound themselves to God by the covenant of a vow, fulfil it not.”6
6 Cat. Rom., P. III, c. 3, qu. 23: “He is to be deemed guilty of the same sin who promises under oath that he will do something, although either he did not have the intention of fulfilling the promise, or, if he did, he does not in fact perform what he promised.”
The validity and binding force of a promissory oath may not be presumed, either morally or legally, but must be proved, for the principal factor is the promise, the oath being merely an accessory to the principal. Hence if the promise was invalid, because of physical or moral inability to keep what was promised, it remains invalid even if an oath was taken to confirm it, and if it becomes invalid later, the obligation arising from the oath ceases, according to the axiom, “Cessante principali cessat accessorium.”
- Unjustifiable or careless swearing (iuramentum vanum sive incautum) is not grievously sinful unless it involves formal contempt of God,7 but it easily leads to perjury and should therefore be avoided.8 To this class of acts belong the oaths of those who habitually call upon God in trivial matters, such as buying and selling, though they really have no intention of taking an oath.9
7 H. Busembaum, S.J., Medulla Theol. Mor., l. III, tr. 2, c. 2, dub. 3, n. 1: “As to judgment, if this alone is lacking, the sin is for the most part only venial, as if someone swears without necessity, whether from a certain levity of mind or from habit.”—Ibid., n. 2: “Nevertheless, even here one can sin mortally or venially according to the amount of negligence which the one swearing admits in investigating the truth or removing the habit.”—Ibid., n. 3: “And thus the state of those is mortal who do not remove the habit of swearing without attention as to whether that which they are accustomed to swear is true or false.”
8 Ecclus. XXIII, 9.—St. Augustine, Epist., 157 (al. 89), c. 5, n. 40: “Avoid swearing as much as you can. For it is better that not even the truth be sworn than that through the habit of swearing one often falls into perjury and always draws near to perjury. . . . Because the Apostle [Paul], a man most firm in truth, swore in his letters, swearing ought not on that account to be a game for us. For it is much safer, as I have said, so far as concerns us, that we never swear. . . . Not because it is a sin to swear to the truth, but because it is a most grave sin to swear falsely, into which he who is accustomed to swear falls the more quickly.” (Migne, P. L., XXXIII, 693).—St. Thomas, Summa Theol., 2a 2ae, qu. 89, art. 3, ad 3: “In an oath there is great danger, both because of the greatness of God, whose testimony is invoked, and also because of the instability of the human tongue, whose words are confirmed by an oath. And therefore these things [justice, judgment, and truth] are more required for an oath than for other human acts.”
9 Cat. Rom., P. III, c. 3, qu. 13: “Of this kind also is the irreligious affirmation of those who swear in a most trivial matter and without any reason or judgment, but from a certain evil habit. We see this done commonly every day by sellers and buyers.”
- To swear unjustly (iuramentum iniustum) means to affirm under oath something that is false or promise something that is forbidden. It is a grievous sin because it involves an abuse of God’s holy name for the purpose of doing evil.10 To keep such an iniquitous oath would, of course, be an additional sin.11
10 St. Thomas, Summa Theol., 2a 2ae, qu. 98, art. 2, ad 1: “He who swears that he will do something unlawful incurs perjury by swearing because of the defect of justice.”—Cfr. H. Busembaum, S.J., Medulla Theol. Mor., l. III, tr. 2, c. 2, dub. 3, n. 4: “As regards justice, he sins mortally who swears that he will do a mortally evil thing, such as that he will kill someone, because it is a grave irreverence to bind oneself, as it were, to mortal sin by divine authority, so that here two kinds of malice concur: one, that he wills evil; the other, that for this purpose he abuses the authority of God, who hates every evil.”—Ibid., n. 5: “But he sins venially who swears to do a venially evil, vain, useless, or frivolous thing, since only light irreverence is deemed present there.”—Ibid., n. 6: “Likewise, he sins venially who swears something contrary to the evangelical counsels, as that he will not enter religion or give alms or a loan.”
11 Gury, Comp. Theol. Mor., I, n. 304: “One who has sworn to do an evil thing is never bound by the oath; indeed, he sins twice if he fulfils the oath, namely against religion and against the virtue to which the matter of the oath is opposed.”
READINGS.—St. Thomas, Summa Theol., 2a 2ae, qu. 98.—IDEM, Comment. in Sent., III, dist. 39, art. 4.—J. B. Wirthmüller, Die moralische Tugend der Religion, pp. 429 sqq.—F. A. Göpfert, Der Eid, pp. 365 sqq.—H. Noldin, S.J., Summa Theol. Mor., Vol. II, pp. 267 sqq.