Jesus Christ · The Sermon on the Mount
Oaths — Let Your Yes Be Yes
By Jesus's day, oath-taking had grown a loophole system: swear “by heaven,” “by Jerusalem,” or “by your own head” and the promise counted as less binding than one sworn in God's own name — a way to sound solemn while keeping a private escape hatch. Jesus shuts every exit, because each one, traced far enough, touches God anyway. His target is the evasion, not the solemn oath. What He asks instead is simpler and harder: let your word alone be enough.
The Text
— Matthew 5:33–37Again, you have heard that it was said to the ancients, ‘Do not break your oath, but fulfill your vows to the Lord.’ But I tell you not to swear at all: either by heaven, for it is God’s throne;The old rule against false swearing — and the first loophole Jesus names.
Simply let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ Anything more comes from the evil one.What He asks instead: a yes that is yes, a no that is no.
Between the two verses above, Jesus names three more escape-hatch oaths in one breath — by earth, by Jerusalem, by your own head (5:35–36) — each one closed for the same reason: there is no such thing as an oath that does not, sooner or later, reach God.
The Four Forbidden Oaths
— closed, and resolved into one word“by heaven”
for it is God's throne
“by the earth”
for it is his footstool
“by Jerusalem”
for it is the city of the great King
“by thy head”
thou canst not make one hair white or black
Let your
Yes be Yes
MATTHEW 5:37
What He Is Saying
— closing every loopholeThe Law forbade false swearing (Lev 19:12); by Jesus's day the Pharisees had built a graded system on top of it. Swear “by God” and you were bound. Swear “by heaven” or “by Jerusalem” or “by your own head” and, in practice, people treated the promise as softer — a way to sound solemn while keeping a private out. Jesus will not allow the distinction: heaven is God's throne, earth is His footstool, Jerusalem is His city, and not even a hair of your head is yours to pledge. Every loophole still touches God. So He closes all of them and gives one instruction in their place — let your word be trusted without needing an oath to prop it up.
The graded-oath system Jesus is answeringheaven, earth, Jerusalem, your head
Rabbinic teaching of the period distinguished oaths by how directly they named God — swearing “by heaven” or by a created thing was widely treated as non-binding, an oath in form only. Adam Clarke, drawing on Lightfoot's research into the rabbis, preserved the actual ruling: “If any swear by heaven, by earth, by the sun, etc.… this is not an oath… If any adjure another by heaven or earth, he is not guilty.” That is exactly the loophole Jesus closes — the sound of an oath with none of its weight.
The two positionsnamed, gracious, no verdict
Absolute prohibition of all oaths, including civil and legal ones — held historically by the Anabaptists and the Quakers, who read James 5:12 as reinforcing an unqualified rule: swear not at all, by anything.
Prohibition of casual, evasive oath-taking, not solemn oaths under lawful authority — the majority historic Protestant and Catholic position, held by the Westminster Confession (ch. 22). Its holders note that Jesus Himself answered under oath at His trial (Matt 26:63–64) rather than refusing to speak.
The Voices on the Old Rule
— the church hears Matthew 5:33Again, ye have heard that it hath been said, Thou shalt not swear falsely, but shalt perform unto the Lord thine oaths. That is, when you take an oath, speak the truth.
Theophylact of Ohrid· Commentary on Matthew (1107), Matt 5:33
Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself--These are not the precise words of Ex 20:7; but they express all that it was currently understood to condemn, namely, false swearing (Le 19:12, &c.).
Jamieson, Fausset & Brown· Commentary Critical and Explanatory on the Whole Bible (1871), Matt 5:33
Thou shalt not forswear thyself - Christ here proceeds to correct another false interpretation of the law. The law respecting oaths is found in Lev 19:12, and Deu 23:23. By those laws people were forbid to perjure themselves, or to forswear, that is, swear falsely. Perform unto the Lord - Perform literally, really, and religiously what is promised in an oath. Thine oaths - An oath is a solemn affirmation or declaration, made with an appeal to God for the truth of what is affirmed, and imprecating his vengeance, and renouncing his favor if what is affirmed is false.
Albert Barnes· Notes, Explanatory and Practical, Matt 5:33
The Voices on Closing the Loopholes
— the church hears Matthew 5:34–36But I say to you, do not 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. Nor should you swear by your head, because you cannot make a single hair white or black. The Jews have always had this wicked habit of swearing by the elements, as the prophetic word often accuses them (Isaiah 65). Whoever swears, worships, or loves the one by whom they swear.
Jerome· Commentary on Matthew (420), Matt 5:34–36
For this reason Jesus prohibits us from swearing by heaven or by the earth. This is in order that we should not give to creation an honor surpassing creation. Do not deify creation. Those who swear, he says, "swear by the greater," as the apostle has said. And he also forbids swearing by Jerusalem. For the earthly Jerusalem is a type of the Jerusalem above, and God swears only by himself, that is, by his own glory.
Cyril of Alexandria· Fragment 63.14 (444), Matt 5:35
By heaven; for it is Gods throne - To swear by that was, if it meant anything, to swear by Him that sitteth thereon, Mat 23:22. Nor by the earth; for it is his footstool - Swearing by that, therefore, is really swearing by God.… Jerusalem - See the notes at Mat 2:1. City of the Great King - That is, of God; called the Great King because he was the King of the Israelites, and Jerusalem was the capital of the nation, and the place where he was especially honored as king.
Albert Barnes· Notes, Explanatory and Practical, Matt 5:34
Neither shalt thou swear by thy head - For these plain reasons: 1st. God commands thee not to do it. 2dly. Thou hast nothing which is thy own, and thou shouldst not pledge anothers property. 3dly. It never did, and never can, answer any good purpose. And 4thly. Being a breach of the law of God, it is the way to everlasting misery.
Adam Clarke· Commentary on the Bible (1832), Matt 5:36
“Let Your Yea Be Yea”
— the church hears Matthew 5:37for whatsoever is more than these cometh of evil--not "of the evil one"; though an equally correct rendering of the words, and one which some expositors prefer. It is true that all evil in our world is originally of the devil, that it forms a kingdom at the head of which he sits, and that, in every manifestation of it he has an active part.
Jamieson, Fausset & Brown· Commentary Critical and Explanatory on the Whole Bible (1871), Matt 5:37
But let your communication be yea, yea,.... That is, let your speech, in your common conversation, and daily business of life, when ye answer to anything in the affirmative, be "yea"; and when ye answer to anything in the negative, "nay": and for the stronger asseveration of the matter, when it is necessary, double these words; but let no oaths be joined unto them: this is enough; a righteous man's yea, is yea, and his no, is no; his word is sufficient.
John Gill· Exposition of the New Testament (1746–1748), Matt 5:37
When is an oath still necessary?Augustine's answer
Augustine, writing after Paul had used oath-language in his own letters, reads Jesus's command as ruling out the habit of swearing, not every possible necessity for it:
And he who has learned that an oath is to be reckoned not among things good, but among things necessary, will restrain himself as much as he may, not to use an oath without necessity, unless he sees men loth to believe what it is for their good they should believe, without the confirmation of an oath. This then is good and to be desired, that our conversation be only, yea, yea; nay, nay; for what is more than this cometh of evil. That is, if you are compelled to swear, you know that it is by the necessity of their weakness to whom you would persuade any thing; which weakness is surely an evil. What is more than this is thus evil; not that you do evil in this just use of an oath to persuade another to something beneficial for him; but it is an evil in him whose weakness thus obliges you to use an oath.
Augustine of Hippo· Catena Aurea by Aquinas (430), Matt 5:37
Where It Points
— the same word, tested and keptAbove all, my brothers, do not swear, not by heaven or earth or by any other oath. Simply let your “Yes” be yes, and your “No,” no, so that you will not fall under judgment.“Swear not… let your yea be yea” — the same command, in the church's own voice.
But Jesus remained silent. Then the high priest said to Him, “I charge You under oath by the living God: Tell us if You are the Christ, the Son of God.” “You have said it yourself,” Jesus answered. “But I say to all of you, from now on you will see the Son of Man sitting at the right hand of Power and coming on the clouds of heaven.”Jesus Himself, under oath before the high priest — He does not refuse to answer.
James 5:12 repeats the command almost word for word, showing how early and how firmly the church heard it. And Matthew 26:63–64 is the test case every position on this page has to answer: when the high priest puts Jesus “under oath by the living God,” Jesus answers. Whatever “swear not at all” means, it did not keep Him silent there.
Closing
Every loophole Jesus names is really the same loophole worn three ways — a way to sound bound without being bound. He removes the whole system and asks for something plainer: a person whose plain word can be trusted, so that nothing more than “yes” and “no” is ever needed to believe them.