The commandment to keep Shabbat as a day of rest is repeated many times in the Tanakh, the Hebrew Bible. (See for example Exodus 31:12-17 quoted below.) The commandment is usually expressed in English in terms of refraining from the doing of work on Shabbat, but the Hebrew term used in the Bible is melakha (מְלָאכָה—plural melakhot), which has a slightly different connotation.
Jewish law (halakha), especially the Talmud Tractate Shabbat (Ch7, Mishna 2), identifies thirty-nine categories of activity prohibited on Shabbat (or thirty-nine melakhot; Hebrew: ל״ט אבות מלאכות, lamed tet avot melakhot), and clarifies many questions surrounding the application of the biblical prohibitions. Many rabbinical scholars have pointed out that these regulations of labor have something in common—they prohibit any activity that is creative, or that exercises control or dominion over one's environment.
Many of these activities are also prohibited on the Jewish holidays listed in the Torah, although there are significant exceptions permitting carrying and preparing food under specific circumstances.
Many Jews disagree about how to interpret these categories. There are often strong disagreements between Orthodox Jews and Conservative Jews or other non-Orthodox Jews.
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