What Is Halacha?
Halacha is the Jewish legal system — the way one walks. It is the operating language of observant Jewish life.
Summary. Halacha (from halach, “to walk”) is the body of Jewish law that develops from the Torah’s 613 mitzvot through the Mishnah, the Talmud, the medieval codes (most importantly the Rambam’s Mishneh Torah and the Tur), and the canonical Shulchan Aruch of Rabbi Yosef Karo (1565) with the Ashkenazi glosses of Rabbi Moshe Isserles. Halacha is binding in Orthodox Judaism, binding-with-modern-application in Conservative Judaism, and treated as a source of values rather than law in Reform Judaism. Halacha covers everything from the kashrut of food to the conduct of business to the laws of mourning.
The development of Halacha can be traced as a stepwise refinement. The Torah commands 613 mitzvot (Talmud Makkot 23b–24a). The Oral Torah — given, in the traditional account, at Sinai along with the Written — develops these into workable law. The Mishnah (compiled by Rabbi Yehudah HaNasi c. 200 CE) is the first written code of the Oral Torah. The Gemara (compiled c. 500 CE in Babylonia; somewhat earlier in the Land of Israel) is the rabbinic discussion of the Mishnah. Together, Mishnah and Gemara comprise the Talmud.
The Geonic period (c. 600–1000) saw the heads of the great Babylonian academies (Sura and Pumbedita) issue responsa applying Talmudic law to new questions. The medieval period produced great codes: the Rambam’s Mishneh Torah (completed 1180), a comprehensive code organized topically; the Tur of Rabbi Yaakov ben Asher (c. 1340); and the Shulchan Aruch of Rabbi Yosef Karo (printed 1565), which became the authoritative code of Halacha. Karo was a Sephardi; Rabbi Moshe Isserles (the Rema, 1530–1572) added Ashkenazi glosses (the Mappah, “tablecloth”) so that the combined work could serve both traditions.
Halacha continues to develop through responsa — the answers of poskim (decisors) to specific questions. Rabbi Moshe Feinstein’s Igrot Moshe (mid-20th century), the Tzitz Eliezer of Rabbi Eliezer Waldenberg, the Yabia Omer of Rabbi Ovadia Yosef, the Iggrot of Rabbi Shlomo Zalman Auerbach — these and many others constitute the working library of contemporary Orthodox Halacha.
The Shulchan Aruch is organized in four sections: Orach Chaim (daily life and the calendar), Yoreh De’ah (forbidden foods, ritual purity, mourning, and miscellaneous), Even HaEzer (marriage and divorce), and Choshen Mishpat (civil and criminal law). For the New Jew, the most immediately useful is Orach Chaim, with its rulings on prayer, Shabbat, kashrut, and the holidays. The Mishnah Berurah of the Chofetz Chaim (Rabbi Yisrael Meir Kagan, 1838–1933) is the standard commentary that brings the Shulchan Aruch to contemporary Ashkenazi Orthodox practice.
Where Denominations Diverge
Orthodox: Halacha is binding, the Shulchan Aruch and Mishnah Berurah are canonical, and rulings are made by recognized poskim. Conservative: Halacha is binding, but the Committee on Jewish Law and Standards (CJLS) can issue takkanot (rabbinic enactments) responding to modern conditions — landmark examples include the 1950 driving teshuvah and the 2006 teshuvah on homosexuality. Reform: Halacha is a source of values and meaning rather than binding law. Reconstructionist: similar to Reform but with stronger emphasis on Jewish civilization. Renewal: hybrid, with Halacha treated as a serious conversation partner alongside spiritual practice.
Sources
Torah: 613 mitzvot, enumerated in Sefer HaMitzvot of the Rambam.
Mishnah (c. 200 CE); Talmud Bavli (c. 500 CE).
Rambam, Mishneh Torah.
Rabbi Yaakov ben Asher, Tur.
Rabbi Yosef Karo, Shulchan Aruch (1565), with Rema glosses.
Chofetz Chaim, Mishnah Berurah.
Further Reading
Menachem Elon, Jewish Law: History, Sources, Principles.
Joel Roth, The Halakhic Process (Conservative).
Mark Washofsky, Jewish Living: A Guide to Contemporary Reform Practice.
Yitzchok Twersky, A Maimonides Reader.