Trustworthy Speech: Let Your Yes Be Yes
Promises seem to be easily broken and very often to act not as a real promise but as a bridge to delay, have more time, mislead, or even manipulate. Directness seems to be replaced for maybe, possibly, and sometimes it's not a commitment, it's a deferral. How can we stand up for Jesus and tell the truth when we can't stand behind our YES's and our NOs?
Jesus did not treat this as a manners problem. He treated it as a question of whether a person's word could be trusted at all, and he answered it in the middle of one of the most demanding sermons he ever preached. He took up an old command that everyone in the crowd already knew, and pressed it further than anyone expected him to go.
"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." Matthew 5:33-37, ESV
The Matthew passages are speaking to the Pharisees and their abuse of the oath process. Creating some that are acceptable to break and others that are not. He would later name the pattern exactly: "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" (Matthew 23:16, ESV).
He is restating the old commands about oaths with the intention of taking away the human manipulation part of it... restoring the drift... into the New Testament.
Jesus rule here is oaths must have the power of being what we say they are. Like God, we need to be able to be trusted to not lie, manipulate, or delay what we have said we will deliver, do, or not.
That is a harder rule to live under than it sounds. Most of the promises we break are never sworn on anything. We don't invoke heaven or Jerusalem before we say we'll be there, we'll handle it, we'll follow through. We just say it, and reality is left to catch up or not.
Scripture is careful here, though, and worth being just as careful with. Elsewhere in the New Testament, James raises something that can sound like the same failure, but isn't.
"Come now, you who say, 'Today or tomorrow we will go into such and such a town and spend a year there and trade and make a profit'— yet you do not know what tomorrow will bring. What is your life? For you are a mist that appears for a little time and then vanishes. Instead you ought to say, 'If the Lord wills, we will live and do this or that.'' James 4:13-15, ESV
Presuming on a future none of us controls is a different problem than promising something we never meant to keep. One is the sin of forgetting we are creatures. The other is the sin of never meaning what we said in the first place.
Underneath all of this is a claim about God before it is ever a claim about us: the power of God's trustworthiness. God's character. If we are to be holy like God is holy we should not lie... People finally lose trust and disengage. Peter says the same thing plainly: "as he who called you is holy, you also be holy in all your conduct, since it is written, 'You shall be holy, for I am holy'" (1 Peter 1:15-16, ESV).
That is where the commandment finally settles. The commandment in Matthew 5 targets yes and no specifically when reality allows those to be found true... but when our word can be found on certain ground, we must remember that obligation to God. Underneath the oath is the commandment to be truthful.
Picture the neighbor who says he'll trim the tree line before storm season, and doesn't, and says it again next spring, and doesn't. Nothing he said was technically false in the moment. But something in the relationship gets quietly, permanently smaller each time.
Or the coworker who tells you, "I'll follow up today," and today becomes a week, and the week becomes the kind of silence you stop expecting anything to interrupt. This can potentially create distrust. There is nothing left further to negotiate. The pressure leaves and so does the demand for effort. How many small deferrals does it take before a person's word stops meaning anything at all?
There is a kind of ledger running underneath all of this, whether we admit it or not. Every time what we promised does not match what we deliver, someone on the other side of that is going to count it... not in the positive column.
This is the ground Jesus is standing on. Let what you say be simply "Yes" or "No"; anything more than this comes from evil (Matthew 5:37, ESV). Not because plain speech is impressive, but because a life that already keeps its word does not need to be dressed up to be believed. Picture it this way: every heaven and earth a person could invoke, and Jerusalem too, because it was the city of the great King. All of it was a door somebody built because the plain word alone had stopped opening it. Jesus tore the door down. What he left in its place is harder to build and impossible to fake: a yes that means yes, and a no that means no, because the person saying them is learning to be trusted the way God can be trusted.
Matthew 5:33-37 · Matthew 23:16 · Matthew 5:17 · James 4:13-15 · 1 Peter 1:15-16
AI was used in the production of this text as an aid to organize, structure, and perform the design work of the manuscript. The prose is human-driven and grounded in the text of Scripture.
Scripture quotations are from The ESV® Bible (The Holy Bible, English Standard Version®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved.
