In its primary meaning, the Hebrew word mitzvah (; Hebrew: מִצְוָה, mīṣvā [mit͡sˈva], plural מִצְווֹת mīṣvōt [mit͡sˈvot]; "commandment") refers to a commandment commanded by God to be performed as a religious duty. Jewish law (halakha) in large part consists of discussion of these commandments. According to religious tradition, there are 613 such commandments.

In its secondary meaning, the word mitzvah refers to a deed performed in order to fulfill such a commandment. As such, the term mitzvah has also come to express an individual act of human kindness in keeping with the law. The expression includes a sense of heartfelt sentiment beyond mere legal duty, as "you shall love your neighbor as yourself" (Leviticus 19:18).

The opinions of the Talmudic rabbis are divided between those who seek the purpose of the mitzvot and those who do not question them. The latter argue that if the reason for each mitzvah could be determined, people might try to achieve what they see as the purpose of the mitzvah, while rejecting the mitzvah itself. The former believe that if people were to understand the reason and the purpose for each mitzvah, it would actually help them to observe and perform the mitzvah. For some mitzvot, the reason is specified in the Torah.