Judaism has three essential and related elements: study of the written Torah (the books of Genesis, Exodus, Leviticus, Numbers, and Deuteronomy); the recognition of Israel (defined as the descendants of Abraham through his grandson Jacob) as a people elected by God as recipients of the law at Mount Sinai, his chosen people; and the requirement that Israel live in accordance with God's laws as given in the Torah.[9] These have their origins in the Iron Age Kingdom of Judah and in Second Temple Judaism.[9]