Judaism is one of the oldest continuously practiced religious traditions in the world, rooted in the covenant between the God of Israel and the Jewish people, expressed in Torah, developed through millennia of rabbinic interpretation, and maintained through unimaginable historical pressures. It is simultaneously a religion, a civilization, an ethnicity, and a set of ongoing arguments — Orthodox, Conservative, Reform, Reconstructionist, Renewal, and secular Jewish identities all claim the tradition as their own. To understand Judaism is to understand a tradition that has survived by arguing with itself and with God.
Each step builds on the last.