Final answer:
Abraham contributed to Judaism by agreeing to the Covenant with God, promising a special relationship and a prosperous land, and by introducing monotheism, establishing a unified worship of one God and an egalitarian ethical system.
Step-by-step explanation:
The Torah attributes several key contributions to Abraham, which are significant to the development of Judaism. One of the most important contributions was Abraham's agreement to the Covenant with Yahweh, which promised a special relationship between God and the Hebrews. In exchange for their worship and devotion, including the circumcision of all male followers, they were promised a land of prosperity. This Covenant established the Israelites as a distinct group with a unique relationship with God, influencing religious practices and identity within Judaism.
Another foundational contribution was the introduction of monotheism through Abraham's rejection of polytheism and his commitment to the worship of one God. This idea radically shifted the religious landscape and had profound implications for ethical systems in Judaism, emphasizing that all individuals are equal before God. The monotheistic belief laid down by Abraham has been a cornerstone in the development of Jewish religious identity and practice and remains a fundamental aspect of Judaism today.