Part II: The Second Commandment.
PART II: THE SECOND COMMANDMENT OF THE DECALOGUE
§ 112. Now that we have spoken about the First Commandment of the Decalogue, let us go on to the Second, whose decree is as follows: “You shall not take the name of the Lord your God in vain; for the Lord will not hold him guiltless who takes His name in vain” [Exod. 20:7]. The two parts are: (1) the prohibition and (2) the threat.
What the name of God is.
The words 
(“the name of God”) mean not the shapes of the letters with which the name of God is written, as if it would quite well satisfy this commandment not to write completely the name “Jehovah” with its own letters and vowel points but write in its place “Elohim” and pronounce it “Adonai,” as the superstitious Jews claim.
Instead, in Scripture “the name of God” means: (1) God Himself. Thus “to call upon the name of the Lord” (Gen. [26:25]), “to love the name of God” (Ps. 5:[11]), “to sing praise to the name of God” (Ps. 9:[2]), etc., is to call upon, to love, and to praise the true God.
(2) Because the true God is to be acknowledged only in the way that He has revealed Himself in His Word, having come forth from the hidden light of His majesty, “the name of God” means anything about God’s essence and will revealed in His Word. John 17:6: “I have manifested Your name to men.” Acts 9:15: “To carry My name before kings.”
(3) “The name of God” means His authority, order, and command. Deut. 18:19: “Whoever will not give heed to My words which he shall speak in My name, I Myself will require it of him.” Jer. 14:14: “The prophets are prophesying lies in My name. I did not send them, nor did I command them.”
(4) It means God’s majesty and glory. Exod. 9:16: “That My name may be told.” Ps. 8:1: “O Lord, our Lord, how admirable is Your name in all the earth.”
(5) It means the worship and confession of God. Mic. 4:5: “All the people will walk, each in the name of the Lord our God.” 2 Sam. 7:13: “He will build a house for My name.”
** It is emphatic and causal that, even though Jehovah Himself is the author and giver of this law, yet He does not say “You shall not take My name” but “the name of the Lord your God in vain.” If we read or hear the name of a prince of this world not without an attitude of reverence, what honor shall we think is owed to the name of our Lord Jehovah, which is “great” (Jer. 10:6), “praiseworthy” (Ps. 113:3), “holy” (Ps. 111:9), and “terrible” (Ps. 99:3)? Besides this, it is the name of “our God,” for He is our God by creation, revelation, acknowledgment, etc. **
“To take in vain.”
§ 113. God forbids taking this name of His in vain. The word 
has a very broad sense. Properly it means “to lift, to elevate.” Ps. 16:4: “I shall not lift up their names on my lips.” Ps. 50:16: “Why do you recite My statutes and take up My covenant into your mouth?” Acts 9:15: “He is a chosen instrument of Mine to carry (βαστάσαι) My name before the Gentiles.” Therefore God wants His name to be lifted up, but not in vain (
), rashly, lightly, or thoughtlessly, for this is the name of the Lord our God. These words show the cause because of which we should not take the name of the Lord in vain: because it is “the name of the Lord our God.”
A warning is added to the prohibition: “God will not hold him guiltless who takes His name in vain.” The words 
mean “He will not absolve; He will not allow to go unpunished.” This is a judicial expression and shows that transgressors of this commandment become guilty of the wrath and punishments of God.
The purpose of this Second Commandment is to forbid the misuse of God’s name and, on the other hand, to require its pious use. This is stated in negative words (from which the positive antithesis must be concluded) because of the corruption of our nature, which is always inclined to profaning God’s name, and because of the heathens’ custom, who would vainly swear by the names of their false gods. Chemnitz’s observation is very beautiful (Loc., de lege, p. 117):
Just as in the other commandments usually some kind of grosser sin is illustrated so that in His judgment [God’s] hatred of the remaining sins may be shown, so here in the reverse the greater [sin] is put forth for consideration under the lesser. You see, people, in their vain and careless use of God’s name without open blasphemy, believe they are guiltless; but because the Second Commandment says, “God will not hold him guiltless who uses His name in vain,” how much less will those who profane and blaspheme God’s name be guiltless?30
** Very many translators relate the sense of the Second Commandment to rashly taking an oath, as the Chaldaic paraphrase renders it: “You shall not swear in vain by the name of your God.” (Philo follows this, Expos. Decal., as does also Josephus, Antiq., bk. 3, ch. 4.) To others it seems to prohibit us from attributing titles of divinity to created and vain things and from using God’s name elsewhere than in our prayers, in teaching the faith, and in the most serious cases. **
The virtues required in the Second Commandment.
§ 114. Therefore because God forbids the taking of His name in vain,31 we conclude on the basis of the antithesis that He wants us to use it in all pious and holy ways. Therefore to the Second Commandment belong the following virtues: (1) To think reverently about the name of God, that is, to think with a grateful heart how great a benefit it is that God came forth from the hidden light of His majesty and revealed His name to us.
(2) To call upon the name of God, that is, in all adversities to invoke the true God in the name of Christ, our Mediator, as He has revealed Himself in His Word. Ps. 105:1: “Oh, give thanks to the Lord; call upon His name.” Ps. 20:7: “We will remember the name of the Lord our God.”
(3) To give thanks to the name of God, that is, to confess with both heart and voice that benefits of every kind come down to us from God and, by this declaration of the benefits of God, to invite others to the knowledge and invocation of God’s name. Ps. 7:17: “I shall sing praises to the name of the Lord.” Ps. 92:1: “It is good to give thanks to Jehovah and to sing praises to Your name, O Most High.”
(4) To preach the name of God, that is, to propagate the heavenly doctrine which God has handed down to us, to instruct others about it that they, too, may be drawn to the true knowledge of God. Ps. 22:22: “I will tell of Your name to my brothers.” Gen. 4:26: “Enosh began to call upon the name of the Lord.”
(5) To confess the name of God, that is, to profess fearlessly and steadfastly the truth as it has been learned from the revealed Word, without any consideration for ill will or perils, in order to show the glory of God and to draw others to a true knowledge of God. Acts 9:14: “Bind all who confess the name of Jesus.” Matt. 10:32: “Who shall confess Me before men,” etc. Also, because the public confession of true doctrine causes an illumination of the glory of God’s name, in the Old Testament confessing the Lord is used to mean praising God’s name.
(6) To praise and glorify God’s name, that is, not only to praise God with the tongue but also to do everything to the glory of God. Ps. 29:2: “Ascribe to the Lord the glory of His name.” Ps. 86:12: “I shall glorify Your name.” Ps. 100:4: “Praise His name,” etc.
(7) To swear by the name of God, that is, when the glory of God or the well-being of a neighbor requires it, to call upon God in an oath to be a witness that we are speaking the truth and to punish severely those who lie. Deut. 6:13: “You will swear by the name of your God.” Isa. 65:16: “Whoever takes an oath in the land will swear by the God of truth.”
(8) To be zealous for the glory of God’s name, that is, out of a genuine love for God and zeal for His divine glory to grieve when God’s name is insulted and despised and to defend Him in the proper place. Num. 25:13: “Phineas was zealous for his God.” Ps. 69:9: “Zeal for Your house has consumed me.”
The sins forbidden in the Second Commandment.
§ 115. On the other hand, because God forbids taking His name in vain, we conclude from this that the Second Commandment forbids the following sins: (1) To think impious and insufficiently reverent thoughts about God; not to realize how great a benefit is the manifestation of God’s name.
(2) Not to call upon God; to be negligent in prayer; to call upon Him, though not legitimately, which happens if we direct our invocation to created things or imagined deities; if we bind the aid and presence of God to a certain place without the Word; if we dictate to God the time and the manner [of answering our prayer]; if we ask for those things that conflict with God’s will and Law; if our prayers rely on our own worthiness; if our invocation is not in the name of Christ, the Mediator; if our prayers are conceived and recited without a true emotion and perception of the heart; if we pray without true repentance; etc.
(3) Not to give thanks; never or rarely to praise the benefits of God; to attribute them to luck or secondary causes; to give thanks coldly and carelessly; to minimize God’s benefits; to misuse God’s gifts and to neglect them.
(4) To pass by opportunities to instruct others; not to make use of the name of God; to hear or speak the name of God with boredom; to mix corruptions into heavenly doctrine; to spread false doctrine; to give credence to the figments of man’s imagination using God’s name.
(5) To deny recognized truth because of fear or the hope of reward or because of obstinate wickedness; not to confess when we are asked; to conceal our faith; to flee persecution by unlawful means; to misuse Christian liberty; to rush into perils without a calling and to claim that this rashness is confession.
(6) Not to praise God or to be cold and neglectful in doing it; to use the Word of God humorously or jokingly; to use God’s name in superstitions, divinations, and incantations either orally or in writing; to misuse God’s name for cursing; to blaspheme the name of God, which happens in many ways: if we utter impious and blasphemous words against God and His Word, if we make the minds of those who have not yet been converted alien from the true religion by destructive scandals and the example of a very wicked life, etc.
(7) To refuse a lawful oath. To perjure, which happens if we confirm a lie with an oath, if we violate our oath, if we swear in order to deceive. To swear unlawfully, which happens in many ways: If we swear foolishly and rashly in unnecessary situations. If our oath does not have these three concomitants: judgment, justice, and truth. (On the part of the one taking an oath is required the judgment of discretion; on the part of the defendant, the truth is required both in the conscience and in the speech of the person swearing; and on the part of the case, justice is required.) If we swear about an unlawful or impossible thing, or about a doubtful or uncertain thing. If we swear by created things or by fictitious deities. If the form of the oath insults God. Also, it conflicts with a legitimate oath to tender an oath to those who are obviously and certainly going to swear falsely, to discharge wickedly what was promised by an unlawful oath, etc. The Scholastics say that there are six ways that perjury is committed: (a) when one knowingly swears falsely, (b) when one swears deceitfully a truth which is thought to be false, (c) when in ignorance one swears to an untruth which he thinks is true, (d) when one does not keep a promise affirmed by an oath, (e) when one swears an illicit thing or something that leads to a destructive end, (f) when one swears without discretion.
(8) To feel no sadness when God’s name is insulted; not to show a serious concern for preventing that with words and deeds; not to prohibit blasphemies when one can and should with respect to his office; to be driven by zeal but not according to knowledge [cf. Rom. 10:2], which happens when that which is not the glory of God is defended as the glory of God and when that which is judged as conflicting with the glory of God and is driven away with zeal actually is not harmful to the glory of God.
§ 116. As regards these individual virtues and vices, statements of Scripture must be gathered from the preaching of the prophets, of Christ, and of the apostles, and the promises and threats should be added as well. In addition, examples should be appended by which God testified that obedience to this commandment is repaid with just rewards and that transgressors are afflicted with deserved punishments. Here the method of what we began does not allow us to do this; therefore let us add a brief explanation [ἐπίγυσιν] of certain questions.
Whether it is lawful to swear.
(I) The question arises: Is it lawful for Christians to swear? The Essenes once denied this, according to Josephus (Bell. Judaic., bk. 2, ch. 8), as did also the Manichaeans, whom the Franciscans follow today ([Ius canonicum,] Ext., De testibus et attestat., c. 51 Nuper nobis) as do the Anabaptists.32
** Chemnitz (Loci, part 2, p. 49): “Two hundred years after Christ many martyrs refused an oath which the magistrate imposed because they thought that Christians were by no means supposed to swear.”33 **
(1) And yet God Himself swears. Gen. 22:16: “By Myself I have sworn.” Jer. 44:26: “Behold, I have sworn by My great name, says the Lord.” Amos 4:2: “The Lord God has sworn by His holiness.” (Cf. Num. 14:21; Jer. 22:5; 51:14; Amos 6:8.)
(2) Christ, the Mediator of the New Testament, swears. Matt. 5:18: “Truly, truly, I say to you.” This is a formula for swearing, as is gathered from Heb. 6:14. Also, though Christ at first remained silent, after the high priest adjured Him “by the living God,” He gave His confession (Matt. 26:[63]).
(3) The angels swear. In Dan. 12:7 the angel raises his hands toward heaven and swears. In Rev. 10:6 the angel swears by “Him who lives forever and ever.”
(4) Saints of the Old and New Testaments swear. Gen. 14:22: “Abraham swore to the king of Sodom.” Gen. 42:15: “Joseph demanded an oath from his brothers.” Josh. 14:9: “Moses swore, saying.” 1 Sam. 20:3 recounts that David strengthened his agreement made with Jonathan with an oath. (Cf. 1 Sam. 24:[22]; 26:10; 26:16.) In Rom. 9:1 the apostle swears: “I am speaking the truth in Christ, I am not lying; my conscience bears me witness in the Holy Spirit.” 2 Cor. 1:23: “I call God to witness in my soul.” (Cf. Rom. 1:9; 1 Cor. 15:31; 2 Cor. 11:31; Gal. 1:20; Phil. 1:8; 1 Thess. 2:5; 2 Thess. 2:1.)
(5) A lawful oath is a virtue of the Second Commandment, and the moral Law was not abrogated in the New Testament. Deut. 6:13: “You will swear in My name.” In Isa. 65:16 the worship of the New Testament is being discussed: “Whoever will swear on earth will swear in the God of truth.” Jer. 12:16: “If they swear by My name, they will be built up in the midst of My people.” Heb. 6:16: “People swear by something greater than themselves,” etc. That this is not evil of itself is also shown from the example of God, who confirms His promise with an oath.
(6) An oath arises from a right faith in God, namely, that we judge that all things are known [to Him] and before His eyes; we also point out that God is a lover of truth and the avenger of the perjury of a liar. 2 Cor. 11:31: “God knows that I am not lying.”
(7) An oath is part of divine worship because we swear by Him whom we profess to acknowledge as the true God. In Heb. 6:16 we read that an oath is made through one who is more excellent and greater. An oath, then, is a kind of confession of God’s preeminence. Rom. 1:9: “God is my witness, whom I serve with my spirit.”
(8) An oath aims to illumine the glory of God and to promote the welfare of one’s neighbor. Surely, then, in its genus it is not a vice. A manifestation of the truth certainly brings glory to God. Heb. 6:16: “In all disputes among men an oath is final for confirmation.” Therefore we conclude with Augustine (Letter 154): “To swear is not a sin; to perjure is.” Thomas ([ST,] 2.2., q. 89, art. 2): “Swearing is lawful; this is clear: (1) From its origin, because the oath was introduced from the faith by which people believe that God has the infallible truth and the universal knowledge of all things. (2) From its end goal, because it is used to end controversies.”
** In controversies over doubtful matters, God wanted an oath to be used (Exod. 22:11). An oath is part of divine worship (Isa. 19:17), where the prophet is prophesying about the heathen who are going to be converted to the true worship of the true God (also Isa. 45:23). Oaths are lawful, as is seen from: (1) Statements of Scripture and the command of God in Deuteronomy 6. (2) Examples, of God Himself, of Christ, of the angels, and of the patriarchs. (3) The commandment of God that an oath must not be broken (Num. 30:3). (4) Rational arguments, which are: (a) the confirmation of faith (Hebrews 6); (b) “the end of every dispute”34 [Heb. 6:16]. **
The objections of our adversaries.
§ 117. The Anabaptists object: “Although formerly in the Old Testament the fathers were allowed to swear, now in the New Testament we are forbidden to swear by Christ (Matt. 5:34) and James (James 5:12).”
We respond. In the same place (v. 17) Christ clearly says that “He did not come to abolish the Law but to fulfill it.” Therefore Christ’s words are not opposed to God’s Law but to the corruptions of the Pharisees, the nature of which is seen in Matt. 23:16, namely: they judged that swearing by God’s name was lawful even in casual conversation and everyday business, in any situation at all and about any matter at all, even if it did not serve the glory of God or benefit one’s neighbor. What they had agreed to with a simple promise they would violate if the opportunity were given, claiming that God was the avenger only of perjury. In fact, they did not think that a person was guilty of perjury before God if he swore not by the very name of God but by heaven, earth, or the temple. Even if what he was swearing to was nonexistent or was false, they did not think he was guilty of perjury before God. Therefore against these corruptions Christ states that one should in no way swear either directly by God or indirectly by created things, that is to say, vainly or rashly or falsely; rather, one should be very careful about making thoughtless oaths in common conversation where matters can be dealt with through a simple yes or no. (See Chemnitz, Harm., ch. 51, p. 358.) [Ius canonicum] (ch. Etsi Christus, De jurejur.): Swearing out of levity is forbidden here, not out of necessity.35 James’s statement, taken from Christ’s words, has the same meaning. Therefore just as the phrase “at all” in Christ’s words is not simply universal but must be limited to the subject at hand [ὑπoκειμένην ὕλην], so also James’s universal declaration must be taken to refer only to rash and frivolous oaths. Augustine enumerates several species of these and shows that all similar ones are prohibited (Sermon 28 de verb. apost.).
** Heb. 6:16 says, “An oath is the end of all controvery.” Therefore the author of the Epistle to the Hebrews did not consider that the reason and necessity for taking an oath had been removed in the New Testament by Christ. Augustine (De mend., ch. 15): “The Lord said, ‘Do not swear at all,’ lest by swearing it become easy to swear, and from being easy it become customary, and then from being customary one fall into perjury. Regarding this James also says ‘that you not fall under condemnation.’” The particle ὅλως [“at all”] should not be referred to the act but to the object of the act, because one must not swear by those objects which are listed there. The Pharisees took the command about oaths to mean that it only forbade perjury while they allowed thoughtless oaths in everyday life. However, Christ sets the true explanation of the Law against this. Augustine (Letter 154): “It seems to me that this was said not because swearing to the truth is a sin but because perjury is a terrible sin.” A universal particle often should be limited to its subject matter; so in this passage the particle ὅλως [“at all”] forbids any oath, namely, [any] frivolous and thoughtless oaths on a frivolous subject. Thus Exod. 20:10: “You shall not do any work on the Sabbath,” namely, any secular work. Luke 7:28: “None has arisen greater than the Baptist,” namely, none among those who have been born in the usual way. Some interpret ὅλως to mean “frequently and repeatedly,” just as διαπαντός is used in Sirach 23:[10]. (See Lyra in his commentary [on this passage].) **
Which oaths are lawful.
§ 118. (II) The question arises: About what matters should one swear? Or What oaths are lawful?
We respond. We should not develop the habit of swearing just because oaths are lawful; instead, we should only come to witnessing with an oath when necessity so demands. Philo (De dec., p. 481) writes very seriously: “It would be most helpful and fitting for a rational creature to abstain from swearing completely and to become so accustomed to telling the truth that his plain speech gains the character of an oath. Secondarily, however, it is as the proverb says, ‘To swear rightly is to navigate [a difficult course].’ ” Philo again (De special. legib., p. 490): “The habit of swearing frequently is proof of a lack of trustworthiness.” Sirach 23:9[–11] calls us away from the thoughtless habit of swearing with these words: “Do not accustom your mouth to an oath, and do not habitually utter the name of God, for you will not be free of blame. The man who swears frequently will be filled with iniquity, and the scourge will not leave his house. If he has sworn needlessly, he will not be justified,” etc. Since these words have been taken from the Second Commandment of the Decalogue, the only oath that is lawful is the one taken about a lawful, possible, certain, just, and good matter when the glory of God and the welfare of one’s neighbor demand it. Hence the various species of legitimate oaths are established:
** One is private, among private citizens, and then only a few; another is public, which is taken solemnly in a public place. **
One is asserting. It asserts or denies something about a present or past thing. Another is promissory, which binds us to do or not to do something. One is voluntary, when someone gives himself to an oath voluntarily. Another is compulsory, when someone is forced to swear unwillingly. One is private and is used by private citizens in partnerships and contracts; another is alien and is imposed [from without] by a magistrate. They call this a “conceived, solemn, and corporal oath.”
** The alien or imposed oath is that which others impose on the oath-taker by authority, such as when a magistrate demands an oath from his subjects, even by force and compulsion. This compulsion is either just, as when a victor imposes an oath of loyalty upon the vanquished; or it is unjust, as when thieves extort oaths from those whom they have criminally attacked. **
Thomas ([ST,] 2.2., q. 89, art. 6): “It is one thing to swear by simply calling a witness, as happens when one swears by God; it is something else to swear by cursing, as happens when one swears by creatures.” The jurists have a judicial oath, a purgatorial oath, an oath of calumny, an oath of horror, etc. Alexander of Hales ([Summa,] part 3, q. 31, membr. 3, art. 1) reduces all swearing to these four kinds:
An oath-taker has a reverence for primary truth, which is God, and calls Him to witness. This happens: (1) According as He is the beginning of all truth, then one swears to God through truth. (2) According as He is the knower of all truth, in which case the formula is “as God is my witness.” (3) According as He is the judge and repayer of rewards to the good, in which case the formula is “as the Lord lives.” (4) According as He is the repayer of punishment to the wicked, and then the formula is “May the Lord add this to me that I not be saved.”
Whether it is lawful to swear by created things.
§ 119. (III) The question arises: Is it lawful to swear by created things?
We respond. Jerome (commentary on Matthew 5) thinks that Christ absolutely disapproved of formulae for swearing by created things as ungodly. In support of this opinion, many passages from the fathers are cited in canon law ([Ius canonicum,] causa 22, q. 1, c. [8] Considera and c. [16] Movet; and causa 22, q. 5, c. [10] Ecce dico).
** Augustine (Letter ad Public.): “It is not lawful to swear by created things as though they were deities; nevertheless it is lawful to call them as witnesses of our calling upon and invoking of God.” Theophylact (on Matthew 5): “God alone swears by Himself inasmuch as He is subject to no one; but in our case, since we have no power of our own, how can we swear by our own head? For it is the possession of another. Therefore calling Him as witness who has the power to avenge is different from asserting that something we say is true by swearing on a particularly precious thing.” The Fourth Council of Carthage (canon 61): “A priest who swears by created things should be rebuked harshly and, if he persists in his sin, must be excommunicated.” **
Some respond to Jerome saying that swearing by created things is condemned only if the fear of God in the oath [religio iurisiurandi] is given to the created things themselves and in so doing some divine power or attribute, such as omniscience or omnipotence, is attributed to them. Jer. 5:7: “They swear by those things which are not gods.” Or [they say] if someone swears rashly and carelessly by creatures under the impression that with such witnesses he can avoid sin against the Second Commandment and that it would not be perjury for him to break [such an oath]. This was the opinion of the Pharisees, against which Christ (Matt. 5:34) sets forth the true explanation of the Law: that rash, futile, and thoughtless oaths are prohibited—even if they are not made expressly by the name of God but by heaven, by earth, by Jerusalem, or by the head of the oath-taker—because even in these formulae God’s name is contained obliquely, indirectly, relatively, and implicitly, seeing as “heaven is the throne of God, the earth His footstool”; “Jerusalem is the city of the great King”; and “no one can make even a single hair of his head white or black” [cf. Matt. 5:34–36]. In addititon, the disgrace that is brought upon created things by the fact that the honor being given them is owed to God alone then falls back on their Creator. Anselm [of Laon] (on Matthew 5): “We should not swear by creatures both because they are good things made by the highest Good and because God dwells in them.” Luther (Enarr. 2. praecepti, Wittenberg Latin, vol. 2): “He who swears by those things which are of God or which are related to Him is always also swearing by God, of whom, in whom, and unto whom all things exist.” Alexander of Hales ([Summa,] part 3, q. 31, art. 9): “To swear by a creature is to call its Creator as a witness of the truth.”
However, because an oath in the proper sense is an act of reverence owed to God alone, oath formulae that do not expressly use the name of God are better called serious adjurations and strong declarations or, at least, indirect oaths to which belong formulae such as these: Deut. 4:26: “I call heaven and earth to witness against you this day.” Gen. 42:15: “As Pharaoh lives.” 1 Sam. 20:3: “As my soul lives,” etc. [Euthymius] Zigabeni reports (Elench. Ismaëlit.): “Mohammad swears by the sun, moon, stars, fiery brightness, animals, and things of this sort.” The Emperor Justinian ordered his new officials to swear “not only by almighty God and His only-begotten Son, our Lord Jesus Christ, but also by the holy and glorious mother of God, the ever-virgin Mary, and by the holy archangels Gabriel and Michael” ([Corpus Iuris Civilis,] novell. 9). King Otto [I] swears to Pope John [XII] ([Ius canonicum,] dist. 63, c. [33] Tibi Dn. Johanni) “by the Holy Trinity, by the wood of the life-giving cross, by the relics of the saints.”36 However, because an oath is a species of honor [cultus] that is owed to God alone, by which the glory of omniscience and omnipotence is attributed to Him, the estates dedicated to the Augsburg Confession do not accept these oath formulae. Thus in the religious Peace of Passau in 1552 they agreed that in the imperial court it would be a matter of freedom for judicial aides and prosecuting and defense attorneys as to whether they wished to swear under this formula or by God and the Gospel. Wesenbecius points out (Parat., de jurejur., no. 6) that this means the hypostatic Word—that is, the Son of God—and not the letter of the Gospel.
** “The formula for swearing among the Jews is this. The person who takes the oath holds the book of the Law in his arms and swears in the holy language [Hebrew] thus: ‘I swear by the God of Israel, by Him who is called gracious and merciful, that I owe this man nothing.’ The judges say, ‘We adjure you by God, by Him who is called merciful, that nothing be in your hand.’ And he responds: ‘Amen’ ” (Schindlerus, Lex., on the word 
). **
On ceremonies used in swearing.
§ 120. (IV) The question arises: What should be done regarding ceremonies that are used in taking oaths?
We respond. It is not out of place for some rituals to be used in taking oaths for the sake of greater reverence. Eleazar swore by putting his hand under Abraham’s thigh (Gen. 24:2) since he was hoping for the Messiah to come from the seed of Abraham. Christians formerly would swear “by touching the grave of a holy martyr” (Gregory, bk. 5, Letter 33), “with their hand on the altar” (Gregory of Tours, Histor., bk. 5, ch. 3), or “by placing their hand on the book of the Gospels” (Sozomen, Histor. eccles., bk. 6, ch. 30). According to the Constitutio Carolina, which they call the Aurea Bulla [“the Golden Bull”], before the election of the Roman king or emperor,37 the princes of the church who were the electors would give an oath before an altar with the Gospel of St. John set on it and would place their hands reverently upon their breast; on the other hand, the secular princes who were electors would give their oath by physically touching that Gospel with their hands. In Deut. [32]:40 and Dan. 12:7, swearing was done by lifting one’s hands toward heaven. From that certainly arose today’s custom of giving a corporal, or solemn, oath by holding straight and upright the first two fingers, the index and middle, to indicate the pledging of soul and body. Some would even have the thumb be lifted to show that the oath is being given to the Holy Trinity. Women swear by putting their right hand against their breast, a custom the ancient Germans used, too, according to Petrus Gregorius (Syntag., bk. 50, ch. 8, no. 30). Today, in addition to touching the book of the Gospels, in some places candles are lighted and other ceremonies are used, though even if these are omitted the integrity of the oath remains.
What oaths must be kept?
§ 121. (V) The question arises: What oaths must be kept?
We respond: “Rescind your promise in promising evil things; in a shameful vow, keep the decree silent which you vowed carelessly, that you do not do it. Wicked is the promise that is fulfilled by iniquity,” as Isidore states ([Ius canonicum,] causa 22, q. 4, c. In malis). “What is sworn badly is fulfilled worse. It is a wretched exigency that is eased by parricide,” says Ambrose (De officiis, bk. 3, ch. 12), where he is discussing Herod’s oath. “An oath should not bind one to wickedness,” as Ambrose also says, releasing Hubaldus from an oath that he made to a concubine.
** Jerome says that an oath stands on the basis of three conditions: “truth, judgment, and justice.” On truth, that one swear that what his conscience dictates is true. On judgment, that one apply judgment with a deliberate mind, swear about a certain and known matter, and pay careful attention to the sanctity of the oath. On justice, that one take an oath about a just, lawful, and possible matter which does not conflict with faith and love. **
Philo writes beautifully (De specialibus legibus ad tria Decal. Praecepta, p. 491): “A person who swears behaves badly and adds fault to fault since he is abusing the oath when he ought rather to have abstained from wickedness. Therefore let him abstain and as a suppliant beseech God to forgive him out of His kindness for his ill-advised rashness by which he acted without thinking in taking an oath. For it is near incurable madness to double your crime when you could unburden yourself of half your guilt.”
On the other hand, if we are speaking of an oath made about a lawful and possible thing, it must be kept scrupulously, even if it seems harsh and difficult. Ps. 15:4[, 1]: “He who swears to his own hurt” (which applies to harming his own possessions) “and does not change shall dwell on the hill of the Lord.” Hence it is readily apparent what should be decided about an oath given to a robber, both in regard to counting out to him a certain amount of money as well as about [promising] to keep silent [about it]. Rauchbar discusses this in detail (Quaest. juris, p. 2, q. 4). To be sure, some outstanding theologians claim that such an oath should be kept, for the sanctity of an oath should be more holy and honorable to us than the loss of money. Furthermore, such an oath is not unlawful in its own category, comparatively speaking, to the extent that one can thereby preserve his life. If it was just and lawful to promise any such thing by an oath, it will also be just and lawful to fulfill those things promised by an oath. Although the Gibeonites deceived Joshua, he did not wish to violate the sanctity of his oath (Josh. 9:18).
** It pleased God that Joshua kept the oath which he had given the Gibeonites. This is clear from the fact that the violation of that covenant, committed by Saul, could not be expiated except by the slaughter of his children (2 Sam. 21:6). **
That we should keep oaths even given to our enemies is clear from 2 Kings [24:20] and Ezek. 17:13. The Scholastics say that a coerced oath is obligatory in the forum of the conscience but not in the exterior forum, and that, accordingly, money sworn to a robber must be given, but that there should be a remedy by which he can get back in court what he has given or declare it to the judge. He should not swear to what he does not wish to declare because this is contrary to fraternal correction, and thus is unlawful.
** The question is not what right someone has against a robber, but how his oath has bound him in his conscience, in which respect theologians say that such an oath is obligatory. In this oath two things are usually promised: first, a certain sum of money; second, permanent silence. As regards the former, the sanctity of an oath is holier than the loss of money. As regards the latter, we say that such injustice and threatened force should be kept silent with regard to this species. That is, the loss suffered at the hands of robbers by virtue of an oath given should not be revealed. And yet with regard to the genus one can tell about it; that is, he can advise the magistrate in general to be watchful and pay attention to the fact that the province should be cleared of all evil men who, it is certain and known, wander here and there, robbing and plundering, and that the public roads be kept safe. (Schmuccius) **
Whether the use of amulets and markings should be approved.
§ 122. (VI) The question arises: Are the superstitious amulets, necklaces of certain things, and [mystic] markings that are used to avert diseases and other evils to be approved?38
We respond. Not at all. For even though they do not involve an obvious pact with the devil, nor is there a rejection of Christ or Baptism, nevertheless such superstition is a sin against the Second Commandment inasmuch as the name of God is taken in vain. God has not given us His Word to the end that we use its individual letters to avert diseases of our body, but that we may be instructed by it to eternal life and to the salvation of our souls (John 20:31). Therefore whatever healings and [medical] observances are not based in nature or in God’s institution are to be deemed superstitious, and their invention is to be ascribed to the devil. Thoughtlessly, therefore, do some physicians approve of this remedy through certain verbal formulas, thus confirming the superstitions of little old ladies (see Aëtius, bk. 8, ch. 50; Trallianus, bk. 9, ch. 4), whether they claim that diseases actually are taken away by their incantations or by accident, to the extent that the confidence and enthusiasm of a sick person are increased by the use of incantations to which he attributes some power, and, as a consequence, the illness is lifted.