Jesus' instruction in Matthew 5 is about oaths, and it lands somewhere unexpected: let your communication be yea, yea; nay, nay. The argument is that a person who needs to swear an oath has already admitted their ordinary word cannot be trusted.
Proverbs 18:21 makes an enormous claim in nine words — death and life are in the power of the tongue. Not influence. Not damage. Death and life.
Luke 16:10 is the one that reframes small dishonesty: he that is faithful in that which is least is faithful also in much. It refuses the distinction between a small lie and a large one, treating them as the same habit at different scales.
The verses
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Proverbs 12:22Lying lips are abomination to the LORD: but they that deal truly are his delight.
Open → Ephesians 4:25Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.
Open → Matthew 5:37But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
Open → Proverbs 10:9He that walketh uprightly walketh surely: but he that perverteth his ways shall be known.
Open → Proverbs 11:3The integrity of the upright shall guide them: but the perverseness of transgressors shall destroy them.
Open → Colossians 4:6Let your speech be alway with grace, seasoned with salt, that ye may know how ye ought to answer every man.
Open → Ephesians 4:29Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.
Open → Proverbs 18:21Death and life are in the power of the tongue: and they that love it shall eat the fruit thereof.
Open → Luke 16:10He that is faithful in that which is least is faithful also in much: and he that is unjust in the least is unjust also in much.
Open → Proverbs 20:7The just man walketh in his integrity: his children are blessed after him.
Open → Search this and more on FirstVerseOpen Ephesians 4:29 on FirstVerse. It sits between two verses about anger, which changes how it reads.
Reading these passages
The reason Paul gives for not lying is not the one anyone expects: Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.
Not because lying is wrong, though he assumes it is. Not because you will be found out, which is Proverbs' argument. The reason offered is anatomical — members one of another, the language he uses elsewhere for a body and its parts.
Which makes deceit a kind of self-injury rather than an offence against somebody else. A hand does not misinform an eye, not because it would be immoral but because the two are the same organism and the misinformation would land back on the hand. Paul is not appealing to conscience. He is pointing out a structural fact and letting it do the work.
Why an oath is an admission
Jesus' instruction sits in the middle of a passage about swearing, and the argument underneath it is sharper than the sentence looks: But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
Swearing an oath means attaching extra weight to one particular statement — this one I really mean. But that implies the ordinary speech carries less, which is a confession rather than a reinforcement. A person whose plain word is reliable has no use for an oath, because there is nothing to upgrade from.
The doubling is worth noticing too. Not yes and no, but yea, yea; nay, nay — the repetition standing in for the emphasis an oath would otherwise supply. Whatever force you were going to borrow from heaven or the temple, you are told to find it in saying the thing twice and meaning it.
The same disposition at two sizes
Luke refuses a distinction almost everyone relies on: He that is faithful in that which is least is faithful also in much: and he that is unjust in the least is unjust also in much.
Read carefully, this is not the slippery slope it is usually taken for. Jesus does not say small dishonesty leads to large dishonesty, as though there were a gradual descent. He says they are the same thing at different scales — that the disposition revealed by a minor lie is the disposition that would produce a major one, given the opportunity and the stakes.
That is a harder claim than the slippery slope, and less comfortable. The slope at least allows you to stop. This says the small lie is not a first step but a sample.
Death and life
Proverbs makes an enormous claim about speech in very few words: Death and life are in the power of the tongue: and they that love it shall eat the fruit thereof.
Not influence. Not harm. Death and life, which is the largest pair the book has available, applied to something everybody does all day without attention.
The second half is stranger than the first and rarely quoted. They that love it shall eat the fruit thereof — the tongue is being described as something that can be loved, and whatever it produces comes back to the person who loved it. Both outcomes are on the table. Whichever you cultivate, you eventually eat.
The book returns to speech more than almost any other subject. The soft answer, the whisperer who separates friends, the fool who utters all his mind, lying lips as an abomination. Taken together it treats words as the primary instrument by which people build or dismantle the world they have to live in.
Straight and bent
Two proverbs on this page describe integrity as a way of walking rather than a quality of character, and the pairing is deliberate: He that walketh uprightly walketh surely: but he that perverteth his ways shall be known. And: The integrity of the upright shall guide them: but the perverseness of transgressors shall destroy them.
The Hebrew for integrity is tom, which carries the sense of completeness or wholeness — being one thing rather than several. The opposite in both verses is not lying exactly but perverseness, a word meaning twisted or crooked.
So the contrast is between a straight path and a bent one, and the practical claim is about walking rather than morality. The straight one is easier. You do not have to remember what you said, or to whom, or which version of it. The crooked path costs more to walk even when nobody is watching, which is the argument Proverbs actually makes and it is economic rather than pious.
The third in the set adds a consequence that outlives the person: The just man walketh in his integrity: his children are blessed after him. Whatever that promises, it is not addressed to the man's own interests.
A higher standard than accuracy
Paul sets a test for speech that most honest people would fail, and it sits between two verses about anger: Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.
The standard is not truthfulness. It is usefulness to the person listening. A statement can be entirely accurate and still fail this test — which is a distinction worth sitting with, because accuracy is usually where people stop.
Colossians gives the same idea a different image: Let your speech be alway with grace, seasoned with salt, that ye may know how ye ought to answer every man.
Salt in the ancient world did two things. It preserved, and it made food edible. Neither is decoration. The metaphor is not asking for speech that is witty or sharp — the modern reading — but for speech that keeps things from rotting and makes them possible to take in.
And underneath all of it sits the bluntest line on the page, which offers no reasoning at all: Lying lips are abomination to the LORD: but they that deal truly are his delight. Two words at the extremes, abomination and delight, with nothing in between.
Common questions
What does the Bible say about honesty and truth?
Jesus' instruction in Matthew 5 is about oaths, and it lands somewhere unexpected: let your communication be yea, yea; nay, nay. The argument is that a person who needs to swear an oath has already admitted their ordinary word cannot be trusted.
Which Bible verse is most quoted about honesty and truth?
Proverbs 12:22 — “Lying lips are abomination to the LORD: but they that deal truly are his delight.”
Why does Jesus say not to swear oaths?
Matthew 5:37 argues that swearing implies your ordinary word carries less weight. Someone whose plain speech is reliable has no need of an oath, because there is nothing to upgrade from.
Does the Bible treat small lies differently from big ones?
Luke 16:10 refuses the distinction. It does not describe a slippery slope but says the same disposition is revealed at either scale — the person unjust in little would be unjust in much, given the opportunity.
Related subjects
Scripture: King James Version, public domain. Last updated August 15, 2026.