Bava Metzia בבא מציעא

Tractate Bava Metzia was originally part of a large tractate called tractate Nezikin, meaning damages, which comprised what are now the first three tractates in the order of Nezikin. Bava Metzia was the middle section of tractate Nezikin, and from this placement it derived its name, which means the middle gate. The remaining part of this super-tractate was divided into Bava Kamma, the first gate, which precedes Bava Metzia, and Bava Batra, the last gate. Each of these three parts has its own central topic.

Bava Metzia deals with issues relating to business, specifically those that the Torah mentions explicitly. The topics discussed in this tractate include the halakhot of lost and found items, the loading and unloading of animals, verbal mistreatment, exploitation, charging interest, feeding workers, depositing and borrowing items, withholding wages, and the prohibition against damaging collateral.

Bava Metzia expresses one of the unique aspects of Torah law, namely, that it does not distinguish between civil law and ritual law. Jewish civil law is based not on a social contract but on requirements defined by Torah law and rabbinic law. Accordingly, interpersonal relationships and civil laws are viewed as part of the relationship between the Jewish people and God. Although there are certain distinctions made by the Torah between civil and ritual law, in general they are interwoven in the Torah text, as can be seen, for example, in Exodus, chapters 21–23; Leviticus, chapter 19; and Deuteronomy, chapters 21–25.

A basic element in Jewish civil law is the integration of compassion with justice. To a large extent, the halakha goes beyond the requirements of justice. The obligation to relate to others with compassion and generosity is not merely a supererogatory addition to one's legal obligations; it is normative halakha that is derived from the conception of the Jewish people as one family. This is the reason for the distinction that one finds between general halakhot that structure economic life, which apply to all, and specific halakhot that apply only to interactions with fellow Jews. The general halakhot are as much a part of the Noahide mitzva to construct a fair legal system, which is incumbent upon all humanity, as they are aspects of Jewish law. By contrast, halakhot addressing interpersonal relationships, such as the obligation to return lost property and the prohibition against charging or paying interest, are not features of a legal system whose only purpose is justice. Rather, they reflect the requirement to have compassion on and care for one's fellow Jew.

The halakhot discussed in tractate Bava Metzia can be divided into four categories. The first category involves halakhot relating to transactions that are an essential part of any legal system. The second category includes halakhot that apply only to transactions between Jews, the rationale for which has been explained above. The third category describes acts that are not punishable by the courts but are discouraged by the Sages. An example of the court's response to one such act would be the curse administered by the court to one who does not keep his word. Finally, the fourth category states halakhot of ethical behavior. These behaviors were practiced by people of high integrity, and they are based on the verse: “That you may walk in the way of good men, and keep the paths of the righteous” (Proverbs 2:20).

There is one concept that is common to all of these areas of halakha and is found throughout Bava Metzia, and that is the concept of ownership. Although an item is usually owned by the person in whose possession it is held, sometimes that is not the case, e.g., when an item is loaned or rented to another, or when it is deposited with another for safekeeping or as collateral for a loan. At other times, the item is not in the possession of its owner because it has been stolen or lost. In each of these cases, the tractate discusses who has halakhic ownership of the item, and who is responsible for safeguarding it and liable for damage caused to the item or by the item.

Ownership of movable property is transferred through specific modes of transaction, whose details are discussed mostly in this tractate. Even in cases where it is clear that someone performed a valid act of acquisition, it is necessary to determine the exact point in time when the ownership was transferred in order to resolve issues of multiple claims of ownership of the item. It is also necessary to determine the point after which neither party can withdraw from a transaction.

The tractate contains ten chapters.

Chapter One primarily discusses how to determine ownership of an item that is claimed by two individuals.

Chapter Two details the halakhot of returning lost items in general, and those of loading and unloading animals.

Chapter Three examines the halakhot of safeguarding a deposit, the responsibilities of bailees, and the halakhot of misappropriation.

Chapter Four discusses the definition of money and business transactions in which one party exploits the other.

Chapter Five contains the halakhot of interest.

Chapter Six addresses hiring craftsmen and their liability for damage.

Chapter Seven describes the halakhot of hiring workers and whether they may eat from the crops they are harvesting.

Chapter Eight contains the halakhot of bailees in general, including the responsibilities of a borrower, as well as the halakhot of renting houses.

Chapter Nine addresses the halakhot of sharecroppers and contractors working a field, as well as the prohibition against withholding wages and destroying an item given as collateral.

Chapter Ten discusses the halakhot relevant to shared ownership of a building or land.