Christianity and Judaism

Christianity and Judaism are the largest and twelfth-largest religions in the world, with approximately 2.5 billion and 14 million adherents, respectively. Both are monotheistic Abrahamic religions that originated in the Middle East.

Christianity began as a movement within Second Temple Judaism, and the two religions gradually diverged over the first few centuries of the Christian era. Today, both religions have denominational differences, but the main distinction is that Christianity recognizes Jesus as the Messiah foretold in the Hebrew Bible, whereas Judaism maintains that the Messiah has not yet arrived and that the era of prophecy concluded early in the Second Temple period.

Early Christianity distinguished itself by determining that observance of Jewish law (Hebrew: הֲלָכָה, romanized: Hălāḵā, lit. 'the Way')—at least in Pauline Christianity—was unnecessary for non-Jewish converts to Christianity. Another fundamental difference is the two religions' conceptions of God. Most Christian denominations believe in a triune God—its members being known as the Father, Son, and Holy Spirit—with the doctrine of the incarnation of the Son in Jesus being of special importance. In contrast, Judaism believes in and emphasizes the oneness of God and rejects the Christian concept of God in human form, let alone a divided one.

Christianity recognizes the Hebrew Bible (referred to as the Old Testament by Christians) as part of its scriptural canon while Judaism does not recognize the Christian New Testament as scripture. Judaism is also heavily informed by the Talmud, which, though not scripture, is still considered foundational to normative Judaism.

The relative importance of 'correct belief' (orthodoxy) versus 'correct practice' (orthopraxy) constitutes another important area of difference. Most forms of Christianity emphasize orthodoxy, focusing on the so-called New Covenant as mediated by Jesus, the Christ, as described in the New Testament. Judaism has traditionally been thought to emphasize orthopraxy, stressing the immutability of the covenants made between God and the Jewish people and the ongoing dialogue between Jews and God through the prophets.

In Christianity, good works would naturally follow from a person's correct belief, but do not contribute to a person's salvation. Some Catholic traditions, such as those of the Franciscans and liberation theology, explicitly value orthopraxy, and praxis is also of central importance in Eastern Christianity, with Maximus the Confessor going so far as to say that "theology without action is the theology of demons."

Christian conceptions of orthopraxy vary (e.g., Catholic social teaching and its preferential option for the poor; the Eastern Orthodox Church's practices of fasting, hesychasm, and asceticism; and the Protestant work ethic of Calvinists and others) but differ from Judaism in that they are not based on Halakha or interpretations of God's dialogue with the Jewish people.

While more liberal Jewish movements may not mandate observance of Halakha, Jewish life remains centered on individual and collective participation in an eternal dialogue with God through tradition, rituals, daily prayer, and ethical actions.