Oaths
Swearing oaths, perjury, and the command not to swear. Part of Ethics.
Passages that substantially address this topic, in date order.
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- Epistle of Barnabas 2.8Anonymous · ca. 70–135 (often ca. 130) · God commanded instead to bear no grudge and swear no false oath.
- First Apology 16Justin Martyr · ca. 150–155 · Christ taught patience, truthfulness without oaths, worship of God alone, and that only those who do his will are true Christians.
- Diatessaron, section 18Tatian · ca. 160-180
- Diatessaron, section 40Tatian · ca. 160-180
- 3Anonymous · 180 (17 July) · The proconsul describes Roman religion and asks for the oath by the emperor's genius.
- 5Anonymous · 180 (17 July) · The proconsul refuses to hear and demands the oath.
- 3Anonymous · Greek rendering of the Latin Passion; date uncertain · The proconsul asks for the oath by the emperor's genius.
- 5Anonymous · Greek rendering of the Latin Passion; date uncertain · The proconsul refuses to listen and demands the oath.
- 3Anonymous · ca. 180–185 · Perennis demands an oath by the emperor's Fortune.
- 6Anonymous · ca. 180–185 · Christians do not swear, but honor and pray for the emperor.
- Miscellanies 5.14.99Clement of Alexandria · ca. 198–203 · Christ's teaching on plain speech and on oaths has parallels in Plato; the Greeks' “voice of God” echoes Moses' “he spoke and it came to be,” and their teaching that the body is earthly echoes the forming of man from dust.
- Miscellanies 7.8.50Clement of Alexandria · ca. 198–203 · The one who knows neither lies nor swears: his whole life is his oath, and he answers simply “yes” or “no,” as Christ taught.
- Miscellanies 7.8.51Clement of Alexandria · ca. 198–203 · A truthful life makes oaths unnecessary; the one who knows keeps faith by his deeds, needs only God's witness and his conscience, and will never deny the truth, even under torture.
- On Idolatry 20Tertullian · ca. 196–211 · Idolatry can creep in through words: Christians may mention pagan gods' names in ordinary speech, but must never call them gods or swear by them, even in common exclamations.
- On Idolatry 21Tertullian · ca. 196–211 · Keeping silent when someone swears or curses by the gods, or cursing back in their name, honors the idols; a Christian should answer with a blessing in God's name.
- On Idolatry 23Tertullian · ca. 196–211 · Signing a written oath by the gods to secure a loan is a real denial even if nothing is spoken, since the soul dictates what the hand writes, as Zechariah “spoke” in writing.
- To the Nations 1.17Tertullian · 197 · Christians are called disloyal because they will not swear by the emperor's genius or call him a god, yet it is pagans who rebel, mock, and curse the emperors.
- Didascalia 5.12Anonymous · first half of the third century
- Against Marcion 2.26Tertullian · 207/208 (third edition, completed later) · God swears by himself because there is no other god to swear by; and when he told Moses “let me alone” to destroy Israel, he was inviting Moses to intercede, prefiguring Christ.
- PG 12:1605 (Ps 118 LXX)Origen · ca. 220-254 · Notes on Psalm 119:106–109 (LXX 118): the believer's oath in accepting God's covenant, virginity as a freewill offering, and the soul in God's hands.
- Refutation of All Heresies, Book 1, preface 3Hippolytus of Rome · ca. 222–235 · The initiate is bound to secrecy by oaths and, still more, by the shame of what he has done.
- Refutation of All Heresies 5.23.2Hippolytus of Rome · ca. 222–235 · Justin sweetens his long books with myths, then binds his followers by dreadful oaths before handing on his mysteries.
- Refutation of All Heresies 5.24.1Hippolytus of Rome · ca. 222–235 · Justin requires an oath of secrecy, citing Paul's “what eye has not seen” and the Lord's oath in the Psalm.
- Refutation of All Heresies 5.27.1Hippolytus of Rome · ca. 222–235 · Justin's initiates swear the oath Elohim swore before the Good one.
- Refutation of All Heresies 9.22.1Hippolytus of Rome · ca. 222–235 · Essenes obey their leader, show mercy, avoid anger, and refuse oaths, since their word is stronger than an oath.
- Commentary on John 32.95Origen · ca. 230–248 · People should be persuaded to set aside rash promises, even sworn ones, rather than persist in them.
- Exhortation to Martyrdom 7Origen · 235 · Denial and an oath by the emperor's Fortune are grave sins; not even the sun, a creature itself, would wish to be worshiped instead of God.
- Homilies on Leviticus 3.4Origen · ca. 238–250 (Rufinus's translation ca. 400–410) · The oath 'to do evil' is the vow to chastise the flesh for the sake of the spirit; the command to 'declare' one's sin means accusing oneself first, before the devil accuses.
- Homilies on Jeremiah 5.12Origen · ca. 240 · An oath must be sworn in truth, with judgment, and in righteousness, not from habit; this is a stage on the way to Christ's command not to swear at all.
- Metaphrase of Ecclesiastes 5Gregory Thaumaturgus · 3rd century · Paraphrase of Ecclesiastes 5: guard the tongue, keep vows, fear God; greed brings no satisfaction, but enjoying God's gifts is good.
- Against Celsus 4.98Origen · ca. 248 · Elephants keep no oaths, and storks feeding their parents and the phoenix burying its father act by nature, not piety; providence made them to teach humans and to point to the Creator.
- Against Celsus 8.65Origen · ca. 248 · Christians will not win rulers' favour by sin or servility, but neither do they provoke them, obeying Paul's command to be subject to the authorities; yet they will die rather than swear by the emperor's Fortune, which is either nothing or a demon.
- Against Celsus 8.67Origen · ca. 248 · Christians hymn only God and his Son, as sun, moon, and stars do, not Athena; nor will they swear by the emperor, since whatever they rightly receive, like bread, wine, and oil, comes from God's providence.
- Commentary on Matthew, Latin Series 16Origen · ca. 244–249 (Latin translation, 4th–5th century) · On the proselyte made twice a son of Gehenna, degrees of punishment, oaths by the temple and altar read as Scripture and the heart, and tithing small things while neglecting judgment, mercy, and faith.
- Commentary on Matthew, Latin Series 110Origen · ca. 244–249 (Latin translation, 4th–5th century) · Adjuring is found in the law, but one who lives by the Gospel, which forbids swearing, should not adjure anyone, nor adjure demons, since Christ gave power to command them; Jesus neither denied nor openly confessed, but turned the doubting high priest's words, like the devil's “If you are the Son of God,” back on him.
- Commentary on Matthew 10.22Origen · ca. 246–248 · Origen reads Herodias’s dancing daughter as the vicious teaching that pleased Herod and silenced prophecy among the Jews, notes that no righteous man in Scripture keeps a birthday, and warns that not every oath should be kept.
- To Quirinus 3.12Cyprian of Carthage · ca. 248–250 (book 3 perhaps later) · Christians are not to swear oaths.
- 18Anonymous · 250 (the text may be later) · The garlands are torn off; they return to prison; Euctemon's apostasy is described.
- Church History 4.15.18Eusebius of Caesarea · ca. 300–325 · The Martyrdom (quoted): the proconsul urged Polycarp to respect his age, swear by Caesar's fortune, and say “Away with the atheists.”
- Church History 6.5.5Eusebius of Caesarea · ca. 300–325 · Basilides refused to take an oath, confessed he was a Christian, and was imprisoned.
- Church History 6.9.5Eusebius of Caesarea · ca. 300–325 · The accusers swore self-curses, but no believer credited them.
- Church History 6.43.18Eusebius of Caesarea · ca. 300–325 · Cornelius: at communion Novatian made people swear by Christ's body and blood never to return to Cornelius.
- Acts of Phileas and Philoromus 1.6Anonymous · ca. 306-311
- Preparation for the Gospel 1.4.10Eusebius of Caesarea · ca. 313–324 · Christians, taught not to swear and to account for every idle word, practice the highest philosophy in speech.
- Preparation for the Gospel 4.7.1Eusebius of Caesarea · ca. 313–324 · Porphyry swears that he has faithfully preserved the sense of the oracles.
- Preparation for the Gospel 5.5.7Eusebius of Caesarea · ca. 313–324 · Porphyry swore to keep his oracles secret.
- Preparation for the Gospel 8.7.4Eusebius of Caesarea · ca. 313–324 · Philo: even a careless vow binds absolutely.
- Preparation for the Gospel 8.7.5Eusebius of Caesarea · ca. 313–324 · Philo: vows over dependents bind them, but priests and superiors may release them.
- Preparation for the Gospel 9.3.13Eusebius of Caesarea · ca. 313–324 · Members swear oaths of piety, justice, honesty, and secrecy.
- Epitome of the Divine Institutes 59.1Lactantius · ca. 314–320 · The follower of God will not curse, perjure himself, or even swear.
- Demonstration of the Gospel 1.6.68Eusebius of Caesarea · ca. 314–324 · Moses forbade false oaths; Christ forbids oaths altogether.
- Demonstration of the Gospel 3.4.35Eusebius of Caesarea · ca. 314–324 · Jesus taught truthfulness without oaths.
- Demonstration of the Gospel 5.3.20Eusebius of Caesarea · ca. 314–324 · God confirmed Christ’s priesthood with an oath.
- Demonstration of the Gospel 5.3.21Eusebius of Caesarea · ca. 314–324 · Hebrews explains the significance of God’s oath.
- Theophany 5.21Eusebius of Caesarea · ca. 325–337
- Book 1, lines 522–545Juvencus · ca. 330 · Lust of the eye and hand; only an adulterous wife may rightly be divorced, for a husband who divorces another exposes her; oaths are forbidden.
- Life of Constantine 2.15.1Eusebius of Caesarea · ca. 337–339 · Licinius made a treaty under oath, then broke it, recruited barbarians, and sought new gods.
- Commentary on Matthew 4Hilary of Poitiers · ca. 353–355 · Hilary expounds the Sermon on the Mount from the Beatitudes to almsgiving: the apostles as salt and light, Christ fulfilling the law, and the Gospel’s stricter precepts on anger, lust, divorce, oaths, retaliation, and love of enemies.
- To the Bishops of Egypt 18Athanasius of Alexandria · ca. 356 · Athanasius challenges the Arians to state their doctrine openly, and recalls how Arius hid his views and swore a false oath before Constantine.
- Letters 85, 86Basil of Caesarea · ca. 357–378 · Basil protests against tax collectors exacting oaths from peasants; a second letter asks a governor to restore grain seized from the presbyter Dorotheus at Berisa.
- Homilies on the Psalms 14.3Basil of Caesarea · ca. 360-378 · On Ps 15:4 Basil explains that the just man despises the wicked however great and honors the God-fearing however lowly, and reconciles the psalm's praise of true swearing with the Gospel's “do not swear at all.”
- Letter 271Gregory of Nazianzus · ca. 360–390 · Gregory tells a bishop that George, who broke a written oath, has been brought to repentance, and asks him to impose a penance whose length matches his compunction.
- Tractates on the Psalms 14.14Hilary of Poitiers · ca. 360–367 · The baptismal renunciation is an oath that must be kept to the end, since former righteousness is lost by later failure.
- Tractates on the Psalms 62.12Hilary of Poitiers · ca. 360–367 · The king, Christ, rejoices; those who swear by him swear by the true God, and the mouths of the wicked are stopped when he comes as judge and every knee bows to him.
- Tractates on the Psalms 118.14.6Hilary of Poitiers · ca. 360–367 · Enlightened by God's word, the psalmist binds himself by oath and firm resolve to keep God's judgments.
- Commentary on Galatians 1.20Marius Victorinus · ca. 360–363 · Paul confirms his account with an oath before God because the Galatians had already strayed from the faith.
- Against Parmenian the Donatist 2.22Optatus of Milevis · ca. 366–385 · The Donatist people swear by their bishops instead of by God, which Optatus likens to the devil's aim in idolatry, that God should be forgotten.
- Question 43, section 3Ambrosiaster · ca. 370–384 · Jephthah’s rash vow, kept from foolish faith, made him his daughter’s murderer and was turned on himself; God ignored the sacrifice, and the innocent daughter gained by dying.
- Ancoratus 112.1Epiphanius of Salamis · 374 · Noah bound his sons by oath.
- Ancoratus 114.1Epiphanius of Salamis · 374 · Noah's sons swore not to encroach on each other.
- Ancoratus 114.5Epiphanius of Salamis · 374 · God avenged the broken oath.
- Panarion (Adversus Haereses), Haer. 1-64 16.4.5Epiphanius of Salamis · 374-377 · Jesus' rebuke of their rules on oaths.
- Panarion (Adversus Haereses), Haer. 1-64 19.1.6Epiphanius of Salamis · 374-377 · Elxai prescribed oaths by salt, water, earth, and other elements.
- Panarion (Adversus Haereses), Haer. 1-64 19.6.2Epiphanius of Salamis · 374-377 · Scripture forbids other gods and oaths.
- Panarion (Adversus Haereses), Haer. 1-64 19.6.3Epiphanius of Salamis · 374-377 · The one who inspired Elxai's oaths is the evil one.
- Panarion (Adversus Haereses), Haer. 1-64 19.6.4Epiphanius of Salamis · 374-377 · Two sayings of Scripture suffice against Elxai's oaths.
- Panarion (Adversus Haereses), Haer. 1-64 29.2.3Epiphanius of Salamis · 374-377 · God's oath means only firm confirmation.
- Panarion (Adversus Haereses), Haer. 1-64 33.6.1Epiphanius of Salamis · 374-377 · The Saviour fulfilled the pure commands by forbidding anger, lust and oaths.
- On Cain and Abel 1.43Ambrose · ca. 375-378 · God's oath is a concession to human weakness, since his word is itself faithful; he kept his oath by giving us an eternal high priest, and we must keep ours.
- Apostolic Constitutions 2.36.5Anonymous · ca. 380 · Perjury and casual oaths are forbidden.
- Apostolic Constitutions 5.11.1Anonymous · ca. 380 · Christians may not swear by idols, name them, or worship them.
- Apostolic Constitutions 5.11.2Anonymous · ca. 380 · Scripture forbids swearing by idols.
- Apostolic Constitutions 5.12.1Anonymous · ca. 380 · The Scriptures also forbid swearing by or worshiping the heavenly bodies.
- Apostolic Constitutions 5.12.5Anonymous · ca. 380 · A Christian must not swear by any created thing.
- Apostolic Constitutions 5.12.6Anonymous · ca. 380 · If Christ forbade swearing even by the true God, swearing by false gods is far worse.
- Apostolic Constitutions 7.3.4Anonymous · ca. 380 · Christians should not swear at all, or at least swear truly.
- On Virgins 3.6Ambrose · ca. 377 · Ambrose dwells on the death of John the Baptist at Herod’s birthday banquet, the reward of a dancing girl, to warn mothers against teaching their daughters to dance and men against the banquets of the wicked.
- Apology of the Prophet David 16Ambrose · ca. 384-390 · No one is without sin: Samson was mastered by love, and Jephthah by a rash vow that cost his daughter’s life.
- On the Duties of the Clergy 3.12Ambrose · ca. 386–390 · Promises that require a shameful act should not be kept, as Herod’s oath and Jephthah’s vow show; Jephthah’s daughter, keeping faith freely, surpasses the philosophers’ Damon and Phintias.
- Exposition of Psalm 118 14.14.2Ambrose · ca. 386-397 · One swears rightly only when one knows what one swears and is firm in mind.
- Exposition of Psalm 118 14.14.3Ambrose · ca. 386-397 · An oath should be preceded by knowledge of the truth.
- Exposition of Psalm 118 14.14.4Ambrose · ca. 386-397 · Christ forbade oaths because he spoke to the weak, so that they would not swear falsely.
- Exposition of Psalm 118 14.14.5Ambrose · ca. 386-397 · God may swear because his oath cannot fail; man should not presume to imitate it.
- Letter 46.1Augustine of Hippo · ca. 386–430 · Publicola, a landowner, asks Augustine eighteen questions on oaths sworn by pagan gods, food and objects connected with idols, and self-defence.
- Letter 47.2Augustine of Hippo · ca. 386–430 · Augustine argues that using the good faith of someone who swore by false gods is not a share in his sin, and that oaths are forbidden to guard against perjury.
- Letter 62.2Augustine of Hippo · ca. 386–430 · The bishops explain that Timothy will abide by their joint decision, his oath binding only his own will, and ask Severus to agree.
- Letter 125.3Augustine of Hippo · ca. 386–430 · Augustine rejects the idea that Pinianus's oath, given under the crowd's pressure, could lawfully be broken, citing Regulus and the Roman censors.
- Letter 125.4Augustine of Hippo · ca. 386–430 · Augustine explains that an oath binds according to the known expectation of those to whom it is sworn, so Pinianus may travel but must keep his promise to reside at Hippo.
- Letter 126.3Augustine of Hippo · ca. 386–430 · Augustine relates how Pinianus offered to swear that he would reside at Hippo if not ordained against his will, and how the people demanded that any future ordination be at Hippo.
- Letter 126.5Augustine of Hippo · ca. 386–430 · Augustine reports that Pinianus swore and signed before the people, and that Augustine's own signature was left incomplete at Melania's objection.
- Letter 126.6Augustine of Hippo · ca. 386–430 · Augustine insists that Pinianus swore in his presence but not at his command, and that the people sought his ordination, not his oath, as God's work.
- Letter 126.10Augustine of Hippo · ca. 386–430 · Augustine cites Paul's oath in 1 Thessalonians 2:5 as precedent for calling God to witness, and asks that the people not be accused of greed.
- Letter 126.11Augustine of Hippo · ca. 386–430 · Augustine tells Albina that an oath must be kept even when given under fear, as even soldiers keep oaths sworn to enemies.
- Letter 157.40Augustine of Hippo · ca. 386–430 · Augustine briefly answers that the church on earth contains good and bad, and advises avoiding oaths, while noting that Paul himself swore.
- Homilies on Matthew 11.8John Chrysostom · ca. 390 · Closing exhortation of Homily 11: learn virtue like children learning letters, one at a time, beginning at home with not swearing and not insulting, practicing with one's wife and household and imposing penances on oneself, until virtue becomes second nature.
- Homilies on Matthew 17.4John Chrysostom · ca. 390 · The Mosaic certificate of divorce was a concession to prevent worse crimes; Christ, having removed anger, forbids putting away a wife except for sexual immorality, makes the man who does so responsible for her adultery, and closes remarriage to the woman put away; he then turns to oaths.
- Homilies on Matthew 17.5John Chrysostom · ca. 390 · Christ forbids oaths by heaven, earth, Jerusalem, or one’s head because all belong to God, rejects excuses of compulsion, and teaches that the oath was a concession to past weakness, as weaning shows that the breast, once good, is outgrown.
- Homilies on Matthew 17.7John Chrysostom · ca. 390 · The habit of swearing can be overcome easily by practice and the watchfulness of one’s household; Chrysostom refuses applause in place of obedience, threatens to bar persistent swearers from the mysteries, and warns by the example of Eli.
- Homilies on Matthew 48.2John Chrysostom · ca. 390 · Herod hears of Jesus and, from fear and vanity, thinks him the beheaded John risen; the evangelist recounts John’s imprisonment for rebuking Herod’s marriage to Herodias and his murder at the birthday banquet after the girl’s dance.
- Homilies on Matthew 48.4John Chrysostom · ca. 390 · Herodias asks for John’s head on a platter so as to silence his tongue; God permits the murder, crowning John and consoling all who suffer unjustly; Chrysostom warns against rash oaths and shows how sexual immorality breeds murder.
- Tractates on Matthew 10.2Chromatius of Aquileia · ca. 388–407 · Chromatius explains that Christ forbids all swearing, since a Christian's every word must be true, and that God swears only for the sake of unbelievers.
- Tractates on Matthew 10.3Chromatius of Aquileia · ca. 388–407 · Chromatius gives two meanings of the prohibition of swearing by heaven, earth, Jerusalem and one's head: to avoid venerating creatures, and because such oaths are oaths by God.
- Homily 13Gregory of Nyssa · ca. 390–394 · On Song 5:8–12 Gregory explains the bride's oath "by the powers of the field" as the gospel's "Yes" (sound faith and a pure life), the wound of love as Christ's love for sinners, and begins the description of the bridegroom as Christ in his incarnate economy and his body the church: white and ruddy for his flesh, "chosen" for his virgin birth without labour, his golden head the sinless first fruits of our nature, his locks the apostles, his eyes the church's overseers.
- Sermon 180.1Augustine of Hippo · ca. 391-430 · James 5:12, echoing Christ's command not to swear at all, raises a hard question, since it forbids not only perjury but swearing, and does so “above all.”
- Sermon 180.2Augustine of Hippo · ca. 391-430 · Swearing is not itself sin, since God swore and the saints swore; perjury lies in the mind, as when one swears to what one thinks false, even if it proves true; because men are easily deceived and swear constantly, Scripture's shortcut is: do not swear.
- Sermon 180.3Augustine of Hippo · ca. 391-430 · Swearing truthfully is not sin, but it walks on the edge of the precipice of perjury, since human minds are easily deceived; only God swears securely, so the safe course is not to swear.
- Sermon 180.4Augustine of Hippo · ca. 391-430 · The Law commands rendering oaths, so swearing truly is not condemned, but perjury is deadly and true oaths dangerous; Augustine, who always avoided this question, believes God led him to it today.
- Sermon 180.5Augustine of Hippo · ca. 391-430 · Paul swore, as the Greek of 1 Corinthians 15:31 shows (νή, “by,” as in νὴ τὸν θεόν, “by God”), and elsewhere called God as witness, so truthful swearing is not sin.
- Sermon 180.6Augustine of Hippo · ca. 391-430 · Calling God as witness (“God knows,” “God is witness”) is an oath just as much as “by God,” and those who deny it only want to lie with God as witness.
- Sermon 180.7Augustine of Hippo · ca. 391-430 · To swear is to render right to what one swears by, pledging it to God; perjuring oneself by God is worse than by one's child, for although God cannot be harmed, the perjurer harms himself and deceives his neighbor.
- Sermon 180.8Augustine of Hippo · ca. 391-430 · The perjurer who seems to prosper is already dead in soul, for as the soul is the body's life, God is the soul's life and departs at perjury; his luxuries are the worms of a dead soul.
- Sermon 180.9Augustine of Hippo · ca. 391-430 · James says “above all, do not swear,” not because swearing is worse than murder or adultery, but to put us on guard against the habit of constant oaths, which most leads to perjury.
- Sermon 180.10Augustine of Hippo · ca. 391-430 · Augustine confesses he once swore habitually and overcame it by fear; he now swears only when necessary for the good of an unbelieving hearer, and the “evil” beyond yes and no is then the hearer's unbelief, as with Paul's oath to the Galatians.
- Sermon 180.11Augustine of Hippo · ca. 391-430 · One who demands an oath from someone he knows will swear falsely is a murderer; some thieves refuse to swear when accused, claiming Christian scruple, yet swear constantly in idle talk; the daily habit of needless oaths must be cut off.
- Sermon 180.12Augustine of Hippo · ca. 391-430 · The habit of swearing requires extra vigilance because the tongue slips easily; even pagans fear to swear falsely by their stone idols, and a Christian who swears falsely by an idol is still a perjurer, since he deceives his neighbor before God.
- Sermon 180.14Augustine of Hippo · ca. 391-430 · Augustine asks his hearers to admonish one another at home, assuring them from experience that if they avoid swearing for three days the habit will die.
- Sermon 307.1Augustine of Hippo · ca. 391-430 · The Gospel of John the Baptist’s beheading shows truth breeding hatred: John told Herod it was unlawful to have his brother’s wife, and Herodias, through her dancing daughter and Herod’s rash oath, had him killed.
- Sermon 307.2Augustine of Hippo · ca. 391-430 · False swearing is so grave a sin that Christ forbade swearing altogether, telling his disciples to let their yes be yes and their no be no.
- Sermon 307.3Augustine of Hippo · ca. 391-430 · God himself swore to Abraham and swore that Christ is a priest forever after the order of Melchizedek, whose offering the faithful recognize; God’s oaths are true and he does not repent of them as Herod did.
- Sermon 307.4Augustine of Hippo · ca. 391-430 · Swearing truly is not a sin, but because false swearing is grave, Christ forbade all oaths, so as to keep us far from the edge; God alone, who cannot lie, swears safely.
- Sermon 308.3Augustine of Hippo · ca. 391-430 · One who swears because another demands an oath to clear a suspicion does not sin as the one who demands it; swearing comes ‘from evil’, the common evil that we cannot see one another’s hearts.
- Sermon 308.5Augustine of Hippo · ca. 391-430 · Augustine tells of Tutuslymeni of Hippo, who forced a debtor to swear falsely and in a dream was beaten by a heavenly judge, waking with the marks; such sin is worse for those warned, so the habit of swearing must be given up.
- The Lord's Sermon on the Mount 1.17Augustine of Hippo · ca. 393–396 · Augustine explains the prohibition of oaths: swearing is not good but sometimes necessary because of others’ weakness, as Paul’s oaths show; the oaths by heaven, earth, Jerusalem, and one’s head are all owed to God.
- Letter 4.96 (to Martianus)Isidore of Pelusium · ca. 393-ca. 435 · Herod the tetrarch's crimes against John the Baptist; three explanations of why his marriage to Herodias was unlawful (Philip had children, so the levirate did not apply; she left a living husband; Herod killed his brother), with Isidore preferring the first.
- On Lying 28Augustine of Hippo · ca. 395 · Paul swore oaths in his letters, showing that Christ's 'do not swear at all' forbids loving or seeking oaths, not every oath.
- On Lying 37Augustine of Hippo · ca. 395 · Readings of Proverbs 30 (LXX) on the son who keeps the word are weighed, as referring to all lies, to lies of the heart, or especially to lies in religious teaching.
- Against Faustus the Manichaean 19.22Augustine of Hippo · ca. 398–400 · Augustine notes that Paul swore oaths, mocks Manichaean swearing by the light and by Mani, and plays on Mani’s name as meaning madness.
- Against Faustus the Manichaean 19.23Augustine of Hippo · ca. 398–400 · Augustine explains Christ’s sayings on murder, adultery, and oaths as clarifying the law, noting that Paul swore in his letters but not in his speeches.
- Against Faustus the Manichaean 19.25Augustine of Hippo · ca. 398–400 · Augustine argues that the law of retaliation set a limit to revenge and that Christ’s command not to retaliate keeps its purpose more safely, just as not swearing guards against perjury.
- Questions and Answers to the Orthodox 27Anonymous · 5th century (disputed) · Moses carried Joseph's bones despite the law against touching the dead because his oath to Joseph was the greater obligation; Scripture often excuses such necessary breaches, and need not explain everything.
- Apology against Rufinus 1.30Jerome · ca. 401–402 · Jerome rebuts the charges of slandering his predecessors and of breaking his dream-oath, arguing that his vow concerned future reading, not memory of what he learned as a boy, and mocks Rufinus's style.
- Apology against Rufinus 1.31Jerome · ca. 401–402 · Jerome replies that a dream cannot bind like a waking oath, retorts with the vows of baptism and monastic life, and warns Rufinus with the Psalms.
- Apology against Jerome 2.1Rufinus of Aquileia · ca. 401 · Rufinus begins Book 2 by denying Jerome's charge that Origenists are pledged to perjury by a teaching in Origen's Stromata, which he says he never possessed or read.
- Apology against Jerome 2.3Rufinus of Aquileia · ca. 401 · Rufinus declares that anyone who teaches that perjury is ever permitted is outside the faith of Christ and the catholic church.
- Apology against Jerome 2.4Rufinus of Aquileia · ca. 401 · Rufinus undertakes to show from Jerome's own writings that Jerome himself has committed perjury.
- Apology against Jerome 2.6Rufinus of Aquileia · ca. 401 · Rufinus quotes Jerome's account of his dream, in which he was beaten before Christ's tribunal as a "Ciceronian" and swore never again to own or read secular books.
- City of God 1.15Augustine of Hippo · 413–426 · Augustine argues from the story of Regulus, tortured to death by the Carthaginians after keeping his oath to the gods, that worship of the gods does not secure temporal happiness.
- City of God 3.2Augustine of Hippo · 413–426 · Augustine mocks the claim that Troy fell for Laomedon's perjury, pointing out that gods who could not foresee it were poor diviners and that Rome was full of perjury without being punished.
- City of God 3.20Augustine of Hippo · 413–426 · Augustine recounts the destruction of Saguntum, Rome's faithful ally, by Hannibal, and argues that the gods who witnessed its treaty did nothing to save it.
- Commentary on Jeremiah 1.69Jerome · ca. 414-419 · Swearing by the living Lord here means confessing him against idols; a true oath needs truth, judgment and righteousness.
- Commentary on Jeremiah 1.92Jerome · ca. 414-419 · God would spare Jerusalem for a single just man, but he values sincere faith, not oaths sworn in his name falsely.
- Apologetic Book 8.4Orosius · ca. 415–416 · Orosius swears his innocence.
- Seven Books of History against the Pagans 3.23.66Orosius · ca. 417–418 · Now Christian faith and oaths keep peace with enemies.
- Seven Books of History against the Pagans 3.23.67Orosius · ca. 417–418 · Oaths sworn on the Gospels now bind barbarians and Romans.
- Seven Books of History against the Pagans 4.5.2Orosius · ca. 417–418 · Carthage perjured itself; Volsinii nearly fell through luxury.
- Against Lying 21Augustine of Hippo · ca. 420 · Lot's offer, made in fear, and David's rash oath against Nabal, made in anger, are recorded in Scripture but are not examples to imitate.
- Against Lying 37Augustine of Hippo · ca. 420 · Allowing even a kindly lie leads step by step to perjury, which some even try to regulate; at least in matters of religion no lie is permissible, and teaching that one may lie cannot be true.
- Against Lying 39Augustine of Hippo · ca. 420 · Even if some lies are pardoned as weakness, no cause can justify perjury or blasphemy, the latter being worse since it says false things about God himself.
- Against Lying 41Augustine of Hippo · ca. 420 · Lies must be avoided or repented of, never taught; perjury and blasphemy are never permitted, not even to bring someone to baptism, and Consentius should refute the Libra and never seek heretics by lies.
- The Conferences 16.28John Cassian · ca. 426–429 · Friendships founded on sworn compacts do not last, since they rest on obligation rather than virtue and the enemy works to break the oath; true concord exists only among the virtuous.
- The Conferences 17.5John Cassian · ca. 426–429 · Germanus explains that they promised in the cave of the Nativity to return, but that returning would harm their progress, while staying would make them liars and perjurers; once back, their elders would never let them leave again.
- The Conferences 17.8John Cassian · ca. 426–429 · Joseph advises that when every choice brings loss, one should choose the lesser loss; a rash promise may be broken, as a single past fault, rather than accept continual spiritual harm, and correcting a bad promise is not inconstancy.
- The Conferences 17.9John Cassian · ca. 426–429 · Peter rightly broke his vow not to let Christ wash his feet, while Herod kept a rash oath and killed John the Baptist; the end must decide whether a decision should be kept.
- The Conferences 17.10John Cassian · ca. 426–429 · Germanus wants to stay but fears Christ’s command to let one’s yes be yes, believing that nothing begun with a broken promise can end well.
- The Conferences 17.26John Cassian · ca. 426–429 · Joseph teaches that even an oath made in passion should be set aside if a sounder judgment finds the other course more just.
- The Conferences 17.29John Cassian · ca. 426–429 · Joseph advises that a secret let slip is better kept by passing over it lightly than by binding the hearer with an oath.
- Part 2, chapter 21Quodvultdeus of Carthage · ca. 445-450 · Jephthah’s rash vow and sacrifice of his virgin daughter, explained as a punishment for testing God, figure Christ’s offering of his own virgin flesh; Christian heroes surpass the Roman exemplars Torquatus, Mucius, and Curtius.