What is the relation between Abraham and judaism?

Answer 1

The tradition of the Jewish people, and the Torah Sages and Talmud, is that Abraham founded Judaism. He lived 3800 years ago. This tradition is implicit in many passages in the prophets (e.g. Isaiah 41:8) and throughout the Talmud (e.g. Yoma 28b) and is borne out by a reading of Genesis.

God calls himself "the God of Abraham, Isaac and Jacob" eighteen times in the Torah, and that is how we address Him every day in the Shemoneh Esrei prayer.

However, Abraham and his descendants observed their traditions voluntarily, until the Giving of the Torah to Moses 3325 years ago, when God made it obligatory.

Abraham (18th century BCE) came from ancestry that had been God-fearing a couple of centuries earlier but had afterwards slipped into idolatry (Joshua 24:2). Nimrod, the idolatrous tyrant, had brought Abraham's father (Terah) from the Semitic ancestral seat near the conjunction of the Balikh and the Euphrates, and instated him in a position of power in his army in the royal Babylonian city of Ur. Nimrod persecuted any who would question his idolatrous cult.

The Kuzari (Rabbi Judah HaLevi, 1075-1141) states that Abraham was gifted with high intelligence; and, as Maimonides (1135-1204) describes, Abraham didn't blindly accept the ubiquitous idolatry. The whole populace had been duped, but the young Abraham contemplated the matter relentlessly, finally arriving at the conclusion that there is One God and that this should be taught to others as well. This is what is meant by his "calling out in the name of the Lord" (Genesis ch.12). As a young man, he remonstrated with passersby in public, demonstrating to them the falsehood of their idols; and our tradition tells how he was threatened and endangered by Nimrod. Later in life, God said to Abraham in prophecy to move to the Holy Land, which is where Abraham raised his family.

He continued his contemplations, eventually arriving at the attitudes and forms of behavior which God later incorporated into the Torah given to Moses. Abraham taught disciples (Talmud, Yoma 28b), gave tithes (Genesis ch.14), strove to raise a family (Genesis ch.15, 17, and 24) which would serve God, made a covenant with God (Genesis ch.15 and 17), welcomed guests into his home (Genesis ch.18) unlike the inhospitable Sodomites (Genesis ch.19), prayed for people (Genesis ch.18), rebuked others when necessary (Genesis ch.20), eulogized and buried the deceased (Genesis ch.23), and fulfilled God's will unquestioningly (Genesis ch.22). He became renowned as a prince of God (Genesis 23:6).

It is therefore clear why God expresses His love for Abraham (Isaiah 41:8) and calls Himself the God of Abraham (Genesis 26:24), and says that Abraham obeyed Him fully (Genesis 26:5). And this is why, according to our tradition, Abraham is credited with having founded the religion which became known as Judaism.

Answer 2

The Jewish belief in one God traces back to Abraham through the Children of Israel, descended from Jacob (who was known as Israel), the son of Isaac, the son of Abraham, who is credited as being the first monotheist.