Moses is the single most decisive figure in Jewish history, and it is not overpraising him to call him the founder of Judaism as we know it today. Although the Bible reports that God revealed himself to Abraham and entered into a covenant with him several centuries before the birth of Moses, the defining events of Judaism took place during the lifetime of Moses--the emancipation of the Israelites, the forty years of wandering that transformed them into a nation, and, above all, the giving of the Law on Mount Sinai, not only the Ten Commandments but the whole body of biblical law that embodies the essential teachings of Judaism and is still observed in all of its rigorous detail by Orthodox Jews throughout the world. This article addresses the historical identity of Moses and discusses his impact on the today's followers. It is also available as part of a series of five articles entitled "Fathers of Faith."