Oaths and the Call to Radical Truthfulness | Matthew 5:33-37
Brian Hedges | February 1, 2026
Let me invite you to turn in your Bibles to Matthew 5. We’re going to be looking at Matthew 5:33-37. This is in our continuing study on the Sermon on the Mount, called “Heirs of the Kingdom.” Let’s jump right in. I’m going to read these words of Scripture.
“Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform to the Lord what you have sworn.’ But I say to you, Do not take an oath at all, either by heaven, for it is the throne of God, or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. And do not take an oath by your head, for you cannot make one hair white or black. Let what you say be simply ‘Yes’ or ‘No’; anything more than this comes from evil.”
This is the word of the Lord.
If you’ve been following along in the series on the Sermon on the Mount, today’s passage may feel a little bit anticlimactic, a little less intense, compared to the last two Sundays. Two weeks ago we saw how Jesus spoke about anger and how contempt and insult are not minor failures but are heart-level violations of the will of the Lord. It’s anger and murder, hatred in the heart.
Then last week, we looked at these words of Jesus where he addresses the issues of lust and adultery and divorce and the implicit call to covenant faithfulness. And of course, those words are emotionally charged, deeply personal words.
Those passages that come before are heated. We could even say they’re somewhat spicy. And then we arrive at Jesus teaching on oaths. There’s no scandal here, nothing that’s obviously controversial. If we’re honest, this passage can feel a little bit vanilla. You might even wonder, “Is this really worth an entire sermon?”
I think that reaction tells us something important: that we underestimate the importance of our words, because Jesus does not treat words as a small matter. In fact, later in Matthew’s Gospel, we read some pretty stunning statements from Jesus, where he tells us that on the day of judgment we will give an account for every idle word we speak (Matthew 12:36). And he also teaches that it’s out of the abundance of the heart that the mouth speaks (Matthew 12:34). That means that our words are not accidental. They reveal what is truly within us. Our words are indicators of the heart. They are an index of our character and of our spiritual condition, and our words are some of the criteria by which we will be judged.
Jesus in this passage stresses the importance of words and calls us to a kind of simplicity and honesty and truthfulness and integrity in our speech.
We remember that he is calling us to a certain kind of life, life in the kingdom of God. The Sermon on the Mount is Jesus’ manifesto of the kingdom. He’s calling us to life under the saving reign of God, and he’s showing us in this passage how the reign of God should shape our words and affect our speech. He’s calling us to nothing less than integrity in our speech, and that makes this passage very relevant to every one of us and very practical, because all of us talk. We talk every day. We say hundreds of words, thousands of words, millions of words in our lifetimes; and, long before any of us will be tempted to something like murder or adultery, we will have spoken thousands of words, words that indicate something about our hearts.
So this passage is important for us to consider this morning. I think the question that Jesus places before us is not simply what words are allowed, what words are not allowed; it’s, rather, what kind of people are we becoming? Are we becoming the kinds of people whose words can be trusted? Are our words reliable? Do we speak with integrity?
This passage will take us from Jesus’ teaching on oaths to our everyday speech, and finally to Christ himself, the one whose word never fails.
1. The Christian and Oaths
Let’s begin with the Christian and oaths, verses 33-36. I think Jesus begins here because oaths, and especially the way oaths were being used in Jesus’ day, revealed a deep disorder of the heart. We remember that Jesus here is not correcting the Old Testament—he comes to fulfill the law, not abolish the law—but what he is doing is correcting the distortions of the law of God that had crept in through the teaching of the scribes and Pharisees.
In the Old Testament, oaths were serious. They were meant to secure truth. To invoke God’s name was to place oneself under divine witness, and the law guarded this speech carefully. The third commandment, “You shall not take the name of the Lord your God in vain.” The ninth commandment, “You shall not bear false witness against your neighbor.”
By the time of Jesus, something had gone wrong. The scribes and the Pharisees, following the rabbis, had developed an elaborate system of distinctions, different kinds of oaths. Some of these oaths were considered binding; other oaths were not considered binding. It all depended on the technicality of the speech. Were you swearing by heaven? Were you swearing by earth? Not swearing by the name of the Lord, but swearing by something less than him? Then maybe you could get out of it.
It reminds me of what I learned as a child, and probably many of us learned as a child, that little saying that goes like this: “Cross my heart, hope to die, stick a needle in my eye.” But if you had your fingers crossed behind your back, it didn’t count. Interesting how even children are being trained in deception.
It’s exactly that kind of attitude, that kind of evasive use of speech, that way of wiggling out from under our commitments, that Jesus is targeting here.
You see this very clearly in Matthew 23, something of a parallel passage, where Jesus directly confronts the hypocrisy of the scribes and Pharisees. Look at this passage. This is Matthew 23:16-22. Jesus says,
“Woe to you, blind guides, who say, ‘If anyone swears by the temple, it is nothing, but if anyone swears by the gold of the temple, he is bound by his oath.’ You blind fools! For which is greater, the gold or the temple that has made the gold sacred? And you say, ‘If anyone swears by the altar, it is nothing, but if anyone swears by the gift that is on the altar, he is bound by his oath.’ You blind men! For which is greater, the gift or the altar that makes the gift sacred? So whoever swears by the altar swears by it and by everything on it. And whoever swears by the temple swears by it and by him who dwells in it. And whoever swears by heaven swears by the throne of God and by him who sits upon it.”
Jesus doesn’t mince words here. He is calling the scribes and the Pharisees blind guides because of how they had used religious language to obscure responsibility. They had used different forms of oaths as tools for manipulation.
Jesus is concerned with how these ways of speaking train people to evade truthfulness and to think that our commitments depend on technical wording rather than the integrity of the heart. So Jesus says very clearly, “Do not swear at all. Let what you say be simply yes or no.”
I do think we have to wrestle with those words. Jesus speaks with absolute categories here, and so the church has had to think through the application of these words.
There have been a variety of positions across the years. The early church fathers, from my limited reading, from what I can tell, took these words at face value, and there was a strict refusal of oaths even under pressure. Now remember, this was during the days of the Roman Empire, and many people, of course, would even lose their lives rather than burn incense before Caesar or take a pagan oath.
You see this reflected in the Eastern church father Chrysostom, who believed in strict refusal of oaths even under pressure. Commenting on this text, he said, “If anyone should require an oath and apply constraint, let the fear of God be more powerful than the constraint.” And so there seemed to be this absolute refusal to take oaths.
That seems to get adjusted after Emperor Constantine professed faith in Christ and the Roman Empire became the Holy Roman Empire; Christendom is born. Now people are taking oaths in the name of Christ or in the name of the Christian God. So Augustine is not absolutely against oaths, but he is concerned with frequency of taking oaths and with how that can form us in bad habits that lead to perjury.
But some Christians, especially in the Anabaptist tradition—this is still true today among Anabaptist theologians; it’s also reflected in Mennonites and Quakers—believe that Christians should never take oaths. No oaths, without exception. They take the words of Jesus seriously, and I think we should respect their reading. Even in our own context, that concern has left its mark in jurisprudence in the United States. There is an allowance for an affirmation instead of an oath for those who object on grounds of conscience.
The reformed position—you see this in Calvin, you see it in the Westminster Confession of Faith—is that there’s a distinction made between lawful oaths, which are allowed but should be rare, but the primary emphasis is on the integrity of our speech. So in matters of weight and truth, when required by rightful authority, oaths can be allowed.
I think it is worth noting that even in the New Testament itself, Paul occasionally uses oath-like language, as he calls God as his witness. And I don’t think Paul would have been intentionally and directly going against the teaching of the Lord Jesus.
So that indicates that Jesus’ command here might not be a blanket prohibition of all oaths in every circumstance. What we know for sure—and this is the main application for this point—is that Jesus here issues a radical summons to truthfulness that, if obeyed, would make oaths unnecessary because we would always and only speak truth.
I think this is what Jesus is calling us to. In honoring him, we neither soften his command nor do we isolate it from the rest of Scripture. We interpret it within the scope of the whole canon of Scripture, but we see that Jesus’ words press us toward a very demanding vision of truthfulness and integrity of speech.
2. The Christian’s Everyday Speech
That shows up especially in our everyday speech—point number two: the Christian’s everyday speech. Most of us will probably very infrequently, if ever, give testimony in a courtroom, but all of us speak every day, and often without thinking. So this passage should prompt us to examine our speech.
Does our speech model what it means to be a citizen in the kingdom of God? Is our speech under the reign of the Lord? What would it look like if it were? I want to suggest three categories.
(1) First of all, purity of speech. The Bible consistently categorizes speech as being either corrupting on one hand or edifying, constructive, building up others on the other. You see this in Ephesians 4:29. Paul says, “Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear.”
Then in the next chapter, Ephesians 5, he says, “Let there be no filthiness nor foolish talk nor crude joking, which are out of place, but instead let there be thanksgiving.”
In both of those verses, he’s giving us two categories. This is very binary. It’s either one way or the other. Your speech is either corrupting others or it is constructive. It’s building up, it’s fitting, it gives grace to others. It is either coarse and filthy and foolish and out of place, or it’s characterized by thanksgiving.
I think when you put those two verses alongside the teaching of Jesus here in Matthew 5…and along with that, James, the brother of our Lord, who essentially repeats this teaching of Jesus in James 5:12, where he says, “But above all, my brothers, do not swear, either by heaven or by earth or by any other oath, but let your yes be yes and your no be no, so that you may not fall under condemnation.” You put all those verses together and one thing it means is this: that purity of speech for the Christian should rule out most of what we consider strong language and curse words that are so often used in our culture—most if not all.
Crude language is considered unfitting for a Christian. Casual swearing using the name of the Lord is a direct violation of the third commandment and a violation of what Jesus says here.
I am concerned here with the way sometimes even Christians speak, flippantly using the name of the Lord. “Oh God.” Just saying it like that: “Oh God.” Or, “Dear Lord,” or “Good Lord,” or even using the name of Jesus in a flippant way. We should honor the name of the Lord and not use the Lord’s name in that way. We should not use language that offends others unnecessarily, language that would call our hearts into question.
Purity of speech is not about trying to sound religious. That’s also a problem. Jesus will confront that kind of facade in our words and in our piety in the next chapter. But purity of speech is speech that honors the Lord, that adorns the gospel, and that ministers grace to those around us.
Friends, we should think through the application of this in all the different spheres of our lives. It touches all of us. It has to do with the tone that you bring into your home at the end of the day, whether your words make things lighter or make things heavier, whether you’re bringing in a kind of negativity and a kind of speech that corrodes and destroys the relationships. It has to do with how easily sarcasm and crude humor and careless profanity can sneak into our language.
I think it also has to do with our witness, because for those who are exploring Christianity, sometimes the first test of authenticity in the Christian will be their words. It’s one of the first things that people will notice who are unbelievers. They’ll notice the difference in the way Christians talk.
Do you remember this in The Pilgrim’s Progress, when Christian and faithful go to Vanity Fair? Vanity Fair is the city that represents the world. And one of the things that distinguishes Christian and faithful in Vanity Fair is that they talk differently. They talk differently! And listen, as a disciple, as a follower of Jesus, you should talk differently than the world. We should not sound like the world.
Again, it’s not exhibiting any kind of artificial spirituality—I’m not talking about that—but it is avoiding anything that dishonors Christ or either hurts or offends or dishonors people. Kingdom speech is speech that gives grace. So for some of us, that is a call for us to clean up our mouths, change the way we talk.
(2) The second application is honesty in our speech. When the Scripture calls us to honesty, it’s not only warning us against obvious lies (it includes that) but also white lies, little lies. It’s calling for an alignment between words and reality.
Listen to two passages from Paul. Ephesians 4:25: “Therefore, having put away falsehood, let each one of you speak the truth with his neighbor, for we are members one of another.”
Colossians 3:9-10: “Do not lie to one another, seeing that you have put off the old self with its practices and have put on the new self, which is being renewed in knowledge after the image of its creator.”
Those two passages together show us that lying belongs to the old life. Lying belongs to the old self, the old man, and we’ve put that away. We’ve put off lying. We’ve put off falsehood, and now we’re called to speak truth.
Again, this means searching out dishonesty in its more subtle forms: when we exaggerate and embellish in order to make ourselves sound more clever or better than we really are, when we tell half-truths to protect us from discomfort, when we lie out of convenience or to save face, when we carefully choose our words so that technically they’re not false, but we’re using those words as tools for manipulation or evasion of the truth.
This matters, of course, in all of our different relationships. This matters in friendship, because friendship is built on shared honesty. Friendship is built on the foundation of truth and trust. It matters at work and at school, where integrity is tested in the way we report to our employers, the way we take tests, that we’re not cheating the system. We’re seeking to be honest. It matters in families, where children learn what truth looks like by the way their parents model it.
I’ll never forget when I was growing up, one time when my parents had been gone for a day, and they came home at the end of the day, and us kids were kind of left to fend for ourselves for supper, and I think we must have asked, “Did y’all get dinner?” And they said no. And about thirty minutes or an hour later, they came back to us, and my mom, with tears in her eyes, weeping, convicted of her sin, because they had told a little lie, because they didn’t want to tell us that they had gotten dinner without us. It was a small thing, but it was a lie. She confessed it with tears because she was convicted of that lack of truthfulness. That just made me, of course, trust her even more.
(3) Honesty of speech, purity of speech, and then number three, integrity of speech. This is a little different. It includes the purity and the honesty, but it’s a little bit different, because this is faithfulness to our words over the long haul.
Psalm 15 describes a person who could dwell with the Lord as one who keeps their word even when it’s costly. Integrity means that your yes and your no are not dependent on convenience, on mood, on outcome, on shifting circumstances. It means that when we say yes, we really mean yes, and we follow through.
Integrity means faithfulness to our commitments. It means showing up when we said we would. It means following through even when our enthusiasm begins to lag. It means resisting the temptation to say yes simply to appear generous or available to others when we have no intention of really following through on that commitment. Jesus says to let your yes be yes, let your no be no.
It means keeping our promises, keeping our word, so that our word represents something. It means a kind of reliability and faithfulness in speech.
To give you an illustration of this, I recently watched the Lord of the Rings films on the big screen. Did you know they’re on the big screen? If you’ve never seen these, you should go see them. If you like fantasy films, you should go see these.
I love these films; I’ve been watching them for twenty-five years. It’s the twenty-fifth anniversary, so they’re on the big screen. I went to see The Fellowship of the Ring a few weeks ago. It’s the first of the film.
If you know the story, it’s the story of these hobbits, these creatures who are entrusted with an evil ring that needs to be destroyed, and all of these different characters band together around them to protect them, to help them on the journey to Mordor. There’s a contrast between some of these different characters and the way they respond to temptation and hardship.
In particular, think of the contrast between this one man, named Boromir—Boromir is a warrior, he’s a prince of Gondor, he’s this man of nobility, this man of valor—and he takes an oath; he makes this vow to protect Frodo and to protect the ring. By the end of the film, his heart has succumbed to the temptation of this evil ring. He wants to take it and use it to defend his city. He betrays that oath, and he betrays Frodo and breaks his word.
In contrast to that, you have Frodo’s companion, Sam. (This is a picture of Frodo and Sam.) Sam is not a warrior, he’s not nobility; he’s just a simple hobbit. He’s a gardener. But there comes a moment in the film when Frodo is going to leave the fellowship. He’s going to go off on his own on this dangerous journey, and Sam risks his life to follow Frodo, to go with him, and he explains why. He says, “I made a promise, Mr. Frodo, a promise; and I mean to keep it.”
Of course, if you know the story, you know that by the end of this whole story, it is the faithfulness of Sam to Frodo that actually sees Frodo through all the hardships of this journey, and it’s his faithfulness to this word. That’s integrity. It’s not loud, dramatic; it’s just faithfulness when it would be easier to turn back.
The Scriptures call us to that kind of integrity in our speech. Jesus says, “Let your yes be yes and your no be no. Anything more than this comes from evil,” or it could be “comes from the evil one.” Jesus wants our speech to be so reliable, our simple yes to be so reliable, that an oath would be unnecessary, because we always tell the truth, we always keep our word.
Now, at this point, you may be feeling some tension, because if you’re honest, you have to say, as I do, that I’ve not always spoken the truth with purity, that there have been times when we have shaded the truth, where we’ve told a half-truth or a white lie. There have been times when we have said yes and we have failed to follow through. We’ve not always been faithful to our commitments. There are times where we have used speech in ways that dishonor God or dishonor others. We have to say that not every word we speak is visibly under the reign of Jesus.
So that raises a question, doesn’t it? What hope is there for people whose words are not always faithful? And the answer to that question is, of course, Christ himself.
3. Christ: The Christian’s Model and Motive
So point number three, Christ, who is the Christian’s model and motive. I want you to see both, how Christ is our model and how this is our motivation, our gospel motivation for living in this kind of way, with our speech reflecting the purity, honesty, and integrity that Christ requires.
When you look at the life of Jesus, one thing that stands out is that his words and his life were never out of alignment. Jesus always spoke truth. Jesus didn’t hedge truth. He did not speak words that were corrosive. There was no impurity in his words. He was the perfect model of purity, honesty, and integrity.
You can see this in 1 Peter 2, where the apostle Peter says, “For to this you have been called, because Christ also suffered for you, leaving you an example so that you might follow in his steps. ‘He committed no sin, neither was deceit found in his mouth.’”
“Neither was deceit found in his mouth.” It wasn’t even in his mouth. There was no deceit in Jesus. He was absolutely true.
The Scriptures press that even further, don’t they? Because Jesus was not only truthful in what he said, the Scriptures tell us that he is the Truth itself. He is the way, the truth, and the life (John 14:6). Jesus is the word made flesh, so that in Jesus, truth is not abstract, it’s not theoretical. Truth is enfleshed. Truth walks and speaks and suffers. We see truth in person as Jesus lives with such truthfulness.
Near the end of the Bible in Revelation 19, we get this wonderful title of Jesus, where he is called Faithful and True. That’s his name. He is faithful and true.
Paul tells us that all of the promises of God find their yes and their amen in Christ (2 Corinthians 1:20). Friends, that means that every promise that God has ever spoken—the promises to Abraham, the promises to Israel, the promises to the church, the promises of the new covenant—all of those promises find their fulfillment and their confirmation in Jesus.
We can even say it this way: Jesus does not just deliver God’s promises, Jesus is God’s promises kept in person. He is the covenant. He is the one who fulfills all that God has promised to us. He is the great model of truth and faithfulness. But because he has been so faithful to us, it is also the motivation for us to be faithful to him.
Listen to Charles Spurgeon. This is a sermon that he preached on Revelation 19:11, where he reflects on that name of Jesus, Faithful and True. Spurgeon said,
“By this you may know your Lord. He has been a faithful and true friend to you. O soldiers of the cross, when has he ever deceived you? When has he failed you or forgotten you? Faithful? Ah, that he is; faithful to every word that he has spoken. And true; do you not recognize him? For is he not the truth, the very truth of God? Has he not kept every promise that he has made you? And have you not found his teachings to be everlastingly settled upon divine veracity? And faithful and true has he been to the great Father. The work he undertook to do he has accomplished. He stood as the surety [that is, the guarantee] of his people, and he has been faithful and true to that smarting suretyship.”
(The word “smarting” means painful.) Even at the cost of his own life, Jesus was faithful! He was true to the very end.
The greatest demonstration of the faithfulness of Jesus, of course, is the cross, where Jesus fulfilled all that God had promised, where Jesus fulfilled his promises to us and he showed his great faithfulness to his people. Friends, that is the great motive for you and I to be faithful and true in our speech.
I don’t want you to hear this message as a legalistic call, as just moralism. I don’t want you to think of simply policing your words and trying not to say the wrong thing. I want it to go deeper than that. This is a message that calls us to a deep integrity between our hearts and our words, and it’s all grounded in the faithfulness of Christ, the confidence that we have in him.
You see, our confidence is not finally in our ability to speak well; it is in the one whose word has never failed. It’s knowing that as we follow him, his faithfulness begins to reshape us, to renew us, to transform us. It means learning to speak truthfully, because we so trust him and his faithfulness to us that we do not need to use words as tools of manipulation to protect ourselves. We can use words simply and truthfully and honestly, because we’re trusting in God’s faithfulness to us. We learn to keep our word because Christ has kept his word to us, and we pursue integrity as we seek to be conformed to the image of the Son.
Let your yes be yes and your no be no. That’s what Jesus calls us to. He’s calling us to a life where our words reflect him, the one who is faithful and true. Let’s pray together.
Gracious God, we thank you this morning that you are a faithful God; that your faithfulness is great, that your mercies are new every morning, and that you have shown that faithfulness to us in a hundred thousand ways. We thank you, Lord, for your promises, and that from the very beginning, when human beings fell into sin, you immediately met that sin with a promise, a promise of one who would come, who would crush the head of the serpent, even at great pain to himself.
We thank you for the promises given to the fathers—the promised seed of Abraham, the promised son who would sit on the throne of David forever and ever. We thank you, Lord, that the good news of the gospel shows us that these promises have been fulfilled in Jesus, and that your plan of redemption has been decisively inaugurated in the person and the work of Christ. We thank you, Lord, for the promises that we still wait to be fulfilled, when Jesus comes again; when he makes all things new, when we will inhabit the new heavens and the new earth and sin and sorrow and suffering and all deceit will be gone once and for all.
Lord, our only confidence is in your word. It’s in knowing that you are a faithful God. Our prayer this morning is that in knowing and in seeing your great faithfulness we would be made faithful ourselves. So we ask you to do that work in our hearts. We pray that you would work in us to will and to work for your good pleasure; that you would work in us that which is pleasing in your sight.
As we come to the table this morning and we receive the elements as these sacred signs, these sacred emblems of your faithfulness to us, demonstrated most fully in the cross and resurrection of Christ, may we receive them as testimonies of your faithfulness, and may we in so doing once again pledge ourselves to you, to live as faithful people whose words reflect the truthfulness of our Lord. So draw near to us in these moments, we pray in Jesus’ name and for his sake, amen.
Brian G. Hedges
