Judaism (from the Latin Iudaismus, derived from the Greek Ioudaïsmos, and ultimately from the Hebrew יהודה, Yehudah, "Judah"; in Hebrew: יַהֲדוּת, Yahedut, the distinctive characteristics of the Judean ethnos) is the religion, philosophy, and way of life of the Jewish people. Originating in the Hebrew Bible (also known as the Tanakh) and explored in later texts such as the Talmud, Judaism is considered by religious Jews to be the expression of the covenantal relationship God developed with the Children of Israel. Rabbinic Judaism holds that God revealed his laws and commandments to Moses on Mount Sinai in the form of both the Written and Oral Torah. This assertion was historically challenged by the Karaites, a movement that flourished in the medieval period, which retains several thousand followers today and maintains that only the Written Torah was revealed. In modern times, liberal movements such as Humanistic Judaism may be nontheistic.

Judaism claims a historical continuity spanning more than 3,000 years. It is one of the oldest monotheistic religions, and the oldest to survive into the present day. The Hebrews / Israelites were already referred to as "Jews" in later books of the Tanakh such as the Book of Esther, with the term Jews replacing the title "Children of Israel". Judaism's texts, traditions and values strongly influenced later Abrahamic religions, including Christianity, Islam and the Baha'i Faith. Many aspects of Judaism have also directly or indirectly influenced secular Western ethics and civil law.