This mitzvah is very practical today. It applies to buying, selling, pricing, negotiating, online sales, used items, services that involve goods, and business deals where one side knows more than the other. A person may not use another person’s ignorance as an opening for gain.

For a seller, this means pricing with honesty. It does not mean every item must be sold at the lowest possible price. Normal profit is permitted. But a seller may not misrepresent value, hide major defects, or charge in a way that crosses into halachic unfairness.

For a buyer, this mitzvah is just as important. A buyer may not pressure someone into selling far below value because the seller does not know the real price. Underpaying can also be אוֹנָאָה — exploitation. Torah does not allow a person to say, “He agreed, so it is fine,” when the agreement was built on ignorance or unfair advantage.

This mitzvah builds a clean business personality. A person learns to ask not only, “Can I get away with this?” but, “Is this fair before Hashem?” The store, contract, invoice, marketplace, and negotiation table all become places of avodas Hashem — service of Hashem.

Rambam

• Source: Rambam, Sefer HaMitzvos, Negative Mitzvah 250; Mishneh Torah, Hilchos Mechirah 12:1–3.
• Rambam defines this mitzvah as the prohibition against wronging another person in a sale. He explains that both the buyer and seller are warned, because אוֹנָאָה — exploitation can happen in either direction. If the seller overcharges, he wrongs the buyer. If the buyer underpays, he wrongs the seller. Rambam’s framing shows that Torah business law protects the fairness of the exchange itself.

Sefer HaChinuch

• Source: Sefer HaChinuch, Mitzvah 337.
• Sefer HaChinuch explains that the root of the mitzvah is to build honest dealings among people. Hashem wants society to stand on trust, fairness, and straight conduct. When people exploit each other in commerce, peace breaks down and suspicion grows. The mitzvah trains a person to see money as an area of responsibility, not only opportunity.

Gemara

• Source: Mishnah Bava Metzia 4:3.
• The Mishnah teaches the basic measure of אוֹנָאָה — monetary exploitation as one-sixth of the value. Below that level, the sale may stand without return. At one-sixth, the extra amount is returned. Beyond one-sixth, the sale can be canceled. This gives the mitzvah clear legal form and shows that Torah fairness is measured carefully.

Gemara

• Source: Gemara Bava Metzia 50b–51a.
• The Gemara discusses the laws of overcharging and underpaying and shows that the prohibition applies to both the buyer and seller. This is central to the mitzvah. The Torah does not only protect the weaker-looking side. It protects the fairness of the transaction, whoever is being exploited.

Gemara

• Source: Gemara Bava Metzia 58b.
• The Gemara connects monetary wronging with the nearby prohibition of אוֹנָאַת דְּבָרִים — verbal wronging. This shows that the Torah is concerned with both money and dignity. A person may not injure another through unfair pricing, and may not injure him through words.

Sifra

• Source: Sifra, Behar, Parashah 3.
• Sifra expounds “אַל תּוֹנוּ אִישׁ אֶת אָחִיו” — “do not wrong one another” as the prohibition against unfair dealing in commerce. The Torah calls the other person “your brother,” teaching that business may not erase brotherhood. Even when money changes hands, the other Jew remains a brother.

Vayikra Rabbah

• Source: Vayikra Rabbah 33:1.
• The Midrash places the laws of honest conduct within the larger demand that Israel live with righteousness before Hashem. Monetary honesty is not a side matter. It shows whether holiness has entered ordinary life. A person’s dealings reveal the truth of his יִרְאַת שָׁמַיִם — awe of Heaven.

Rashi

• Source: Rashi on Vayikra 25:14.
• Rashi explains that “אַל תּוֹנוּ” in this pasuk refers to אוֹנָאַת מָמוֹן — monetary exploitation. This means the Torah forbids wronging another person through unfair buying or selling. His explanation keeps the mitzvah practical and direct: the marketplace must be honest.

Ramban

• Source: Ramban on Vayikra 25:14.
• Ramban explains that the Torah warns both sides in commerce because business can become a place where people quietly harm one another. The command protects the covenantal bond between Jews. A sale is not only a private financial exchange. It is part of the moral life of Klal Yisrael.

Ibn Ezra

• Source: Ibn Ezra on Vayikra 25:14.
• Ibn Ezra reads the pasuk as a warning not to wrong another person in buying and selling. His plain reading highlights the balance of the verse: whether one sells or buys, he must not exploit. The mitzvah applies whenever one side has the chance to take unfair advantage.

Sforno

• Source: Sforno on Vayikra 25:14.
• Sforno explains that the Torah forbids unfair dealing because trade must preserve justice between people. Commerce can easily become a place of hidden wrongdoing. The mitzvah demands that business be guided by truth, not only by desire for gain.

Rabbeinu Bachya

• Source: Rabbeinu Bachya on Vayikra 25:14.
• Rabbeinu Bachya teaches that the Torah’s warning in business is tied to fear of Hashem, because many financial wrongs are hidden from other people. A person may fool the buyer or seller, but he cannot fool Hashem. The mitzvah trains inner honesty where public pressure may be weak.

Chizkuni

• Source: Chizkuni on Vayikra 25:14.
• Chizkuni explains that the Torah warns against wronging a fellow Jew in sales, whether through price or value. His explanation shows that the mitzvah is not limited to obvious fraud. Even a deal that appears normal may be forbidden if one side is unfairly harmed.

Kuzari

• Source: Kuzari 3:11.
• The Kuzari presents Torah law as shaping a holy society through details of justice and daily conduct. אוֹנָאָה — exploitation belongs to this system because business is where trust is tested constantly. A Torah society is not only holy in prayer. It is holy in the marketplace.

Maharal

• Source: Maharal, Nesivos Olam, Nesiv HaEmes, Chapter 1.
• Maharal teaches that אֱמֶת — truth is the foundation of lasting order. Commerce without truth creates separation and distrust. The prohibition of אוֹנָאָה — exploitation protects the straightness of human relationships and keeps money from becoming a force of falsehood.

Ran

• Source: Ran, Derashos HaRan, Derush 11.
• Ran explains that Torah law builds a nation where justice reflects Divine order. Monetary law is not only practical regulation. It teaches how human society should mirror Hashem’s justice. The prohibition of overcharging and underpaying forms a marketplace governed by Torah, not only by power.

Rashba

• Source: Rashba, Teshuvos 3:227.
• Rashba discusses how halacha evaluates transactions and financial claims with precision. His approach shows that Torah commerce depends on real value, real consent, and clear terms. The mitzvah of אוֹנָאָה — exploitation protects the deal from being built on unfair imbalance.

Shulchan Aruch

• Source: Shulchan Aruch, Choshen Mishpat 227:1.
• Shulchan Aruch rules that one who overcharges or underpays violates the prohibition of אוֹנָאָה — monetary exploitation. The law applies to both the buyer and seller. This is the practical heart of the mitzvah: a transaction must not be used to take unfair money from another person.

Shulchan Aruch

• Source: Shulchan Aruch, Choshen Mishpat 227:2–4.
• Shulchan Aruch explains the levels of אוֹנָאָה — exploitation. If the unfairness is less than one-sixth, the sale stands. If it is one-sixth, the extra money must be returned. If it is more than one-sixth, the harmed party can cancel the sale. Halacha gives fairness a precise structure.

Rema

• Source: Rema, Choshen Mishpat 227:6.
• Rema discusses cases where people clearly accept unusual pricing or where market conditions affect value. This shows that אוֹנָאָה — exploitation depends on real context. Halacha does not erase normal market judgment, but it also does not allow hidden unfairness.

Sma

• Source: Sma, Choshen Mishpat 227:1.
• Sma explains that the prohibition applies because the Torah wants business to be conducted with fairness and awareness of true value. The wrong is not only the lost money. It is the misuse of a transaction that should have been honest.

Shach

• Source: Shach, Choshen Mishpat 227:1–2.
• Shach clarifies practical applications of אוֹנָאָה — exploitation and how the halachic measures are applied. His discussion shows that business honesty requires knowledge, not only good intentions. A person must learn enough halacha to avoid unfair gain.

Chasam Sofer

• Source: Chasam Sofer, Toras Moshe, Behar, s.v. “אַל תּוֹנוּ.”
• Chasam Sofer explains that the Torah places monetary honesty inside the holiness of Parshas Behar. Business is not outside avodas Hashem — service of Hashem. A Jew’s conduct in pricing and negotiation reveals whether he truly lives with Hashem’s law in ordinary life.

Netziv

• Source: Netziv, HaEmek Davar on Vayikra 25:14.
• Netziv emphasizes the Torah’s language of “עֲמִיתֶךָ” — your fellow and “אָחִיו” — his brother. The buyer or seller must be seen as a brother, not as a target. The mitzvah protects the moral closeness of Klal Yisrael even inside financial exchange.

Rav Shimshon Raphael Hirsch

• Source: Rav Shimshon Raphael Hirsch on Vayikra 25:14.
• Rav Hirsch teaches that Torah law demands moral self-control in commerce. The marketplace can become a place where sharpness is praised even when it harms others. This mitzvah teaches that business success may not come from exploiting another person’s lack of knowledge.

Malbim

• Source: Malbim on Vayikra 25:14.
• Malbim distinguishes the wording of selling and buying in the pasuk and shows that both sides are warned. The seller must not overcharge, and the buyer must not underpay. The Torah’s language is balanced because exploitation can come from either side of the deal.

Meshech Chochmah

• Source: Meshech Chochmah on Vayikra 25:14.
• Meshech Chochmah reads the mitzvah as part of the Torah’s effort to keep society from being ruled by hidden power. Money can create quiet forms of pressure. By forbidding אוֹנָאָה — exploitation, the Torah protects trust and brotherhood within daily economic life.

Rav Moshe Feinstein

• Source: Igros Moshe, Choshen Mishpat 1:49.
• Rav Moshe Feinstein discusses modern monetary questions with careful attention to market value, agreement, and fairness. His approach shows that אוֹנָאָה — exploitation remains active in contemporary commerce. New kinds of sales and business forms still require Torah honesty.

Tanya

• Source: Tanya, Likutei Amarim, Chapter 37.
• Tanya teaches that mitzvos draw holiness into the physical world. Business honesty is one of the clearest ways this happens. When a person refuses unfair profit, he brings kedushah — holiness into money, goods, and daily dealings.

Sfas Emes

• Source: Sfas Emes, Behar 5637.
• Sfas Emes teaches that the laws of Parshas Behar reveal that ownership itself belongs under Hashem. A person may buy and sell, but he may not treat money as independent from Torah. Avoiding אוֹנָאָה — exploitation shows that financial life is held inside Hashem’s truth.

Kedushas Levi

• Source: Kedushas Levi, Behar, s.v. “וְכִי תִמְכְּרוּ.”
• Kedushas Levi reads the Torah’s language of “your fellow” and “your brother” as a call to compassion inside commerce. A Jew must not let business make his heart cold. The mitzvah teaches that even while negotiating, he stands before another child of Hashem.

Shem MiShmuel

• Source: Shem MiShmuel, Behar 5672.
• Shem MiShmuel explains that money can pull a person into self-interest unless it is guarded by kedushah — holiness. The prohibition of אוֹנָאָה — exploitation refines the desire to gain. It trains a person to let truth rule even when profit is possible.

Ramchal

• Source: Ramchal, Mesillas Yesharim, Chapter 11.
• Ramchal warns that monetary desire is one of the hardest areas to keep clean, because a person can justify many forms of gain. This mitzvah belongs to that work of נְקִיּוּת — cleanliness. A person must not only avoid theft. He must remove subtle unfairness from his business life.

This mitzvah appears in Parshas Behar, in the Torah’s laws of land, sale, return, and economic life. The pasuk speaks directly to buying and selling: when you sell to your fellow or buy from your fellow, do not wrong one another. The Torah places business inside the covenant, not outside it.

Mitzvah 500 is closely related to Mitzvah 501, which forbids harming another person with words. Chazal distinguish between אוֹנָאַת מָמוֹן — monetary exploitation and אוֹנָאַת דְּבָרִים — verbal wronging. One protects a person’s money; the other protects his dignity. Together, they teach that a Jew may not use power, knowledge, or speech to harm another person.

The mitzvah also belongs to the broader system of דִּינֵי מָמוֹנוֹת — monetary laws. Torah business is not measured only by contracts and consent. It is measured by fairness before Hashem. A sale may look ordinary, but the Torah asks whether it was honest, balanced, and free of exploitation.