What Is A Mitzvah?

What is the definition of a Mitzvah? How many are there? And how much does one have to observe them?

The Hebrew root of the word “Mitzvah” is “Tzivah,” which means “to command.” The Mitzvot (plural of Mitzvah) are the commandments found in the Torah (the Five Books of Moses). We refer to Rabbinical enactments as “Rabbinical Mitzvot.”

There is a tradition that G-d included 613 commandments in the Torah. Of these, 248 are positive (a command to perform an action), while 365 are negative (a command to refrain from an action). Many of these Mitzvot, however, deal with the laws of purity and sacrifice, and were thus applicable only when the Temple stood in Jerusalem. Therefore, of all the commandments, only 369 apply today (126 positive, 243 negative). Even of these, however, many pertain only to special cases or circumstances. The total number of commandments which apply to everyone under all conditions is 270 (48 positive, 222 negative). According to Jewish tradition, when the Messiah comes and the Temple is rebuilt in Jerusalem, all 613 Mitzvot will be restored.

By Rabbi Ari Lobel
From JewishAnswers.org