Judaism is the oldest of the Abrahamic monotheistic faiths and the tradition from which both Christianity and Islam historically emerged. It is simultaneously a religion, a culture, a people, and a civilization — a combination that makes it unusually difficult to define in any single dimension. To be Jewish may denote adherence to a religious tradition, membership in an ethnic community, or both; the complexity of Jewish identity has been a subject of philosophical and theological discussion within Jewish thought for centuries, and does not yield a simple answer.
There are approximately 15 to 16 million Jews worldwide, making Judaism demographically one of the smaller world religions. Yet its influence on world history and culture — through its own theological and legal tradition, and through its foundational role in the formation of Christianity and Islam — is vastly disproportionate to these numbers. Western civilisation's concept of linear historical time, the category of prophecy, the idea of a God personally invested in human history and morality: these are inheritances from the Hebrew Bible that pervade thought and culture far beyond the boundaries of the Jewish community.
Origins: Abraham and the Covenant
The founding narrative of Judaism centres on Abraham, whom tradition identifies as a Hebrew chieftain originally from Ur of the Chaldees — a city in ancient Mesopotamia (modern southern Iraq). The biblical account describes Abraham's departure from Ur at God's call, his journey to the land of Canaan, and the establishment of a covenant (brit) between God and Abraham's descendants: God's promise of the land, of offspring as numerous as the stars, and of a special relationship, sealed by the rite of circumcision.
This covenant is renewed with subsequent generations — with Abraham's son Isaac and grandson Jacob, whose twelve sons become the eponymous ancestors of the twelve tribes of Israel. The name Israel derives from Jacob's new name following a night-long wrestling contest with a divine figure: one who "strives with God." The foundational experience of the nation, however, is the Exodus from Egypt — the liberation of the enslaved Israelite people under Moses, the revelation of the divine name YHWH (the Tetragrammaton, often rendered Yahweh or Jehovah) at Mount Sinai, and the giving of the Torah. Jewish theology and practice are centred on this covenant relationship with YHWH and the obligations — the mitzvot, the commandments — it entails.
Sacred Scripture: Torah and Tanakh
The primary scripture of Judaism is the Torah — the five books of Moses: Genesis (Bereshit), Exodus (Shemot), Leviticus (Vayikra), Numbers (Bamidbar), and Deuteronomy (Devarim). These books, corresponding to the Pentateuch of Christian usage, are understood in traditional Jewish theology as divinely revealed to Moses at Sinai — both the written text and an accompanying oral tradition. The Torah is the central object of Jewish liturgy: the handwritten parchment scroll (Sefer Torah) is kept in the ark of honour in every synagogue and read publicly on a fixed weekly cycle throughout the year.
The broader Hebrew Bible, known in Jewish tradition as the Tanakh, comprises three sections: Torah (the five books of Moses), Nevi'im (the Prophets — including the historical books of Joshua, Judges, Samuel, and Kings, and the classical prophets Isaiah, Jeremiah, Ezekiel, and the Twelve Minor Prophets), and Ketuvim (the Writings — Psalms, Proverbs, Job, the Five Megillot, Daniel, Ezra, Nehemiah, and Chronicles). The acronym Tanakh is formed from the initial letters of these three sections.
The Talmud and Rabbinic Tradition
Alongside the written Torah, Jewish tradition holds that God revealed at Sinai an oral Torah — a body of interpretation and legal elaboration that was transmitted orally through the generations and eventually committed to writing. This oral Torah was first codified in the Mishnah (c. 200 CE), compiled by Rabbi Judah ha-Nasi from the accumulated legal discussions of the tannaitic sages. The Mishnah became the subject of further generations of rabbinic debate and commentary, eventually producing the Gemara. The Mishnah together with the Gemara constitutes the Talmud.
There are two versions of the Talmud: the Jerusalem Talmud (Talmud Yerushalmi, compiled c. 400 CE) and the more authoritative Babylonian Talmud (Talmud Bavli, compiled c. 500–600 CE). The Babylonian Talmud is a vast and intricate work — 2,711 folio pages in the standard Vilna edition — containing not only legal discussion (halacha) but also narrative, legend, biblical interpretation, ethical teaching, and occasional philosophical reflection (aggadah). It remains the central text of traditional Jewish study to the present day.
Major Concepts in Jewish Theology
Central to Jewish theology is the absolute unity and uniqueness of God — articulated in the Shema, the watchword of Jewish faith: "Hear, O Israel, the Lord is our God, the Lord is One" (Deuteronomy 6:4). This radical monotheism rejects any form of divine plurality (hence the rejection of Christian Trinitarian theology) and any representation of God in physical form. The covenant relationship between God and the Jewish people gives Jewish theology a distinctive historical and communal character: God is encountered not primarily in abstract philosophical contemplation but in the history of a people and in the practice of a community life shaped by divine commandment.
The 613 mitzvot (commandments) traditionally enumerated from the Torah govern every dimension of Jewish life: prayer, diet (kashrut), sexual ethics, business conduct, the agricultural year, relations with others. For traditional Judaism, the fulfillment of these commandments is itself the means of relationship with God and the expression of Jewish identity.
Major Contemporary Movements
Modern Jewish life is characterised by several major religious movements reflecting different responses to modernity and Enlightenment: Orthodox Judaism, which maintains the binding authority of traditional halacha; Conservative (Masorti) Judaism, which accepts historical development of halacha while maintaining its authority; Reform Judaism, which understands Jewish practice as subject to evolution in response to changing circumstances; and Reconstructionist Judaism, which understands Judaism as an evolving civilisation rather than a divinely revealed system.
For scholarly reference, the Encyclopaedia Britannica entry on Judaism is authoritative. Primary texts are available at sacred-texts.com's Judaism section, including the Bible, Talmud extracts, and Midrashic literature. The Wikipedia article on Judaism provides extensive further reading. The Stanford Encyclopedia of Philosophy's entry on medieval Jewish philosophy covers the great tradition of Jewish philosophical theology.
On this site: Christianity and Islam are the two Abrahamic traditions that emerged from the Jewish scriptural and theological inheritance.