The Complex Halacha of Reneging On An Agreement Or Purchase
Rabbi Moshe Taub
March, 2026, Ami Magazine
Part I
Imagine a choleh who calls his frum pharmacist and says, “I have a horrible case of strep. Do you have antibiotic X?… You do? Great! I will be sending over my chavrusa to pick it up.”
After the choleh hangs up, his doctor calls. “Good news! It was a false positive! It’s just a bad flu—no need for antibiotics.”
Would the choleh be violating any halachic or ethical boundary by canceling the prescription—an agreed-upon business transaction?
Here’s another scenario:
Say someone negotiates a price of $10,000 for a new dining-room set and agrees to pick it up and pay for it the next day. That night, a long-lost cousin dies, leaving the shopper a stunning…dining-room table!
Must he nevertheless pay for the set he agreed to purchase?
Category One: Giving One’s Word and ‘Mechusar Emunah‘
Chazal state that someone who reneges on a verbal business agreement—whether the buyer or the seller—is called a mechusar emunah (literally, one who lacks complete faith in G-d).
Many sources and allusions to this law are cited by Chazal and poskim.
These include, but are not limited to:
- the vitality of honesty (Shemos 23:7);
- the demand that we speak only the truth (Devarim 23:24, with Chida in Pnei David);
- the need to be true to ourselves—echad b’lev v’echad b’peh (Tehillim 15:2);
- and admonishment against words of deceit (Tzefaniah 3:13).
Chazal also find reference to this halachah in the pasuk mandating that we have correct weights and measures (Vayikra 19:36). The Torah uses the examples of two weights, the eiphah and the hin. Why both? Chazal remind us that “hin” can also mean “yes.” The Torah is telling us that one’s “yes” and one’s “no” must be solid and reliable, just like weights (Bava Metziah 48-49).
This same halachah is taught in another mishnah from a more positive perspective, in that our chachamim are pleased with those who keep their word when they conduct sales (Sheviis, 10).
Although a minority opinion interpret these sources as establishing a Torah law (Sema, 204:12), the vast majority see this demand as rabbinic (which can affect the final halachah in some cases, see, for example, shu”t Shevet Halevi, 4:206).
Importantly, most poskim extend this injunction to matters other than money, such as promising someone a gift, a job, or a ride. Some poskim posit further that this prohibition even covers backing out from what one said to a third party—for example, “I will take Yankel to the airport” (see shu”t B’tzel Hachachmah 5:160).
There are also unique cases where this halachah may not apply. An example of this is when the person asserting the fact does not have the power, or sole power, to give the promised item. An example of this may be a school board member assuring a teacher that he will be hired, or a shul board member promising to hire a rav (see Piskei Hamishpat, p. 163, note 25).
Another example would be the assurance of a very large matanah (see Shulchan Aruch with meforshim, Choshen Mishpat, siman 204:7-9; see further in shu”t B’tzel Hachachmah, ibid.).
Of course, any promise regarding a mitzvah may involve separate concerns. For instance, although a minority of poskim contend that a gemach that needs to backtrack on a promise may not always be in violation of mechusar emunah (since the items aren’t gifts per se, but loans; cf. shu”t Shevet Halevi 4:207), nevertheless, because the promise entails a mitzvah, it may constitute a neder (see Piskei Hamishpat, ibid., #19; see also the Rema, yoreh de’ah, siman 264:1, about reneging on the hiring of a mohel).
This brings us to the common refrain “bli neder.” Although many people say this habitually and often needlessly— e.g., “I will take my suit to the cleaners today, bli neder”—regarding tzedakah and other mitzvah matters we should accustom ourselves to saying it .
When Circumstances Change
What if circumstances change? Is it ever permissible to default on a promise or business arrangement?
There are certain situations termed trei tar’i, an open, changing, or mixed market where defaulting on a verbal agreement would fall into the category of normal business conduct and therefore be allowed.
For example, let’s say Reuven did his due diligence in his search for a contractor. Finally, he makes a verbal agreement to hire Dovid’s company for a given sum. The next day, a young kid knocks on his door, explains that he’s just starting out, and offers a half-off deal. According to many poskim, reneging on the initial verbal agreement would be permissible.
The same principle is true even when money is not the issue. For example, if someone agrees verbally to hire a certain moving company and then discovers another one that can do the job in half the time, he may back out of his original agreement.
To gauge these subjective changes, the Sema offers us the following guideline. In any case where you never would have agreed to the original deal if you had known about the second offer, a rav should be consulted, and you may be able to backtrack on your word (Sema, siman 333:1; for trei tar’i to be considered a possibility, the person’s initial research must have been thorough enough that he would not have missed an obvious second option—see Piskei Hamishpat, note 30).
These cases can become complex when one is searching for a chasunah hall, a band, a summer rental, or another such need, and a rav must be consulted (see Shulchan Aruch 333:8 and 334:1, Pis’chei Hachoshen, kinyanim, especially shu”t Chasam Sofer in several places).
In the cases of the pharmacist and the dining-room table, one may, perhaps, be able to rely on trei tar’i. Nevertheless, a rav should be consulted.
Part 2
Before further exploring these complex halachos of mechusar emunah—Chazal’s harsh designation for a buyer or seller who backs out of a deal -let us quickly review what we have learned thus far:
- According to many poskim, the demand that we stand by our verbal agreements applies equally to non-monetary commitments—for example, making a pledge to clean up one’s office by a certain time.
- Above we discussed the common situation called trei tar’a, where a verbal agreement is made regarding an open, changing, or mixed market—a situation where defaulting on a verbal agreement would be considered normal business conduct, and would often be permitted.
For example, one may make a verbal agreement to hire a builder, only to discover another builder who can do the work for half the price or in half the time. In such a case, he may be able to back out of the original agreement.
A more common example of this nowadays would be reserving several flights, Airbnbs, or rental cars until one settles on the cheapest or most convenient option (when not actually purchased or a down-payment given).
- We ended above with the Sema’s simple gauge for testing such a change. In any case where one can honestly and fairly claim that if he had been aware of the second offer earlier, he would never have agreed to the initial offer, he should call a rav as he may be able to back out of the deal (Sema, siman 333:1).
An important caveat to the Sema’s rule: even in a case where the Sema would otherwise allow one to back out, it would not apply if he did not do thorough-enough research that would have led him to the second option before committing to the first one (see Piskei Hamishpat note 30).
Now let us move on:
Mi Sheparah
So far, we have been discussing verbal agreements, where no money has changed hands. A much more severe category of these halachos is called “mi sheparah.”
This is a case that has extended past a verbal agreement, where either money has been exchanged or some other accepted form of transaction has taken place. In such a case, even though the buyer has not yet taken possession of the item, the Mishnah teaches that if either the buyer or the seller backs out, he is subject to a klalah (curse): “Mi sheparah… He Who exacted recompense from the dor haflagah shall also exact retribution from those who do not abide by their word.”
The Gemara cites a debate in which Rava opines that we do not simply inform the person of this curse; instead, beis din actually pronounces it against him (Bava Metzia 48b)!
Although it is not commonly practiced in this manner today, the Maharam Mintz (d. 1480) quotes the Mordechai who describes the procedure of giving just such a curse.
“He [perhaps the rav] stands on the migdal [tower or highest stage] in front of the tzibbur and announces, ‘Mi sheparah… He who exacted…shall similarly exact from Ploni ben Ploni’” (see shu”t Maharam Mintz, 101, bottom of second column in the 1851 edition).
The Rema alludes to this opinion in stating that some add the word “mimcha, from you” at the end of the curse, as opposed to “from one who.”
More frightening is the fact that the Gemara adds to the curse, and it is this lengthier version that is codified in the Shulchan Aruch (Choshen Mishpat, siman 204:4):
“He Who exacted recompense from the people of the generation of the flood, from the citizens of Sedom and Amorah, from the men of the dor haflagah, and from the Egyptians who were drowned in the sea shall also exact retribution from those who do not abide by their word.”
Many seek connections among these examples.
For some time, I suggested an approach that I recently learned was for alluded to in the writings of the Avnei Nezer, who says that he heard it directly from the Chiddushei HaRim (shu”t, chelek 7, end of teshuvah #32).
Each of the situations mentioned in this curse occurred before Matan Torah. The Jewish people were not Jewish yet, and the wrongs committed by the members of these generations involved breaches of basic morality that would be commonly understood to be wrong even without a Divine command.
Furthermore, these people had a rationale for their behavior. For example, they abided by the letter of the law, stealing items that were worth less than a perutah. In the case of the Egyptians, they could have claimed that enslaving the Jews was simply a fulfillment of the decree at the bris bein habesarim. But the fact is that they breached human decency and committed injustices that make it impossible for a society to function normally.
(Indeed, Ramban says that although the Egyptians were fulfilling the will of Hashem, they could have refused to be the vehicle, and, they also went much too far in their brutality.)
Here, too, a beis din may not be able to enforce retribution—but Hashem is aware and will make sure justice is carried out.
- When it comes to a case of mi sheparah, where money has already changed hands—as opposed to the category of mechusar emunah—the principle of trei tar’a would not be enough to enable one to back out of the deal. But what if something occurs that is beyond his control?
For example, say a person gives a down payment on a new dining-room table. On the way to pick it up, he discovers that a long-lost cousin has died and bequeathed him a beautiful dining-room table! Must he still go through with his purchase?
Although there is a minority opinion that would permit a person—in an extreme case and in a situation of trei tar’a— to back out of a deal even after money was paid, most disagree (see shu”t Chasam Sofer, Choshen Mishpat, 120, discussing a case of yerushah; see also Tosfos on Bava Metzia 47b, s.v. v’iy).
Nevertheless, each case is different, and a competent posek must be consulted.
- According to many, mi sheparah applies to a seller who accepts payment but does not have the item in stock. Should he fail to retrieve it, he will have fallen into the category of mi sheparah (Rambam, mechirah, 22).
- What about a case where one writes his name down as a commitment to purchase an item, or one who says, “I will buy it; take the money out of what I owe you”? Would these cases constitute mi sheparah if he reneges? And what about land purchases, which also fall into this halachic category (see Beis Yosef)?
The goal of this post is to remind ourselves of these two critical halachos, and to emphasize the need to consult a rav when such an issue arises.
The Vilna Gaon shares a secret that is contained in this curse (Sefer Yehoshua, perek 4). He writes that speech is made up of saliva (water), ruach (air), and heat (fire). In fact, the letters in the word “amar” (to speak) stand for eish, mayim, and ruach. Each of the first three incidents mentioned in the curse represent one of these: the dor hamabul was destroyed by water; the dor haflagah was destroyed by wind in the sense that the people were scattered; and Sedom and Amorah were destroyed by fire.
In other words, what mi sheparah has in common with these events is the misuse of speech.
May we all succeed in our business dealings and in our speech. May we speak only divrei emes and utter tefillos that will be immediately accepted! ●
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