How did Abraham become the father of the Hebrew nation if he was not genetically a Jew?
Abraham became father of the Hebrew nation not by genetic descent but by his call and covenant promises. Though Scripture regards him as father of the Jewish race, his blood remained Syrian; he was genetically a Syrian from Ur of the Chaldees. Isaac, the son of promise, was the first real Jew by birth.
Les explains that the Jewish nation was not yet on the scene when Abraham lived. Abraham was a Syrian, and he had two brothers up in Syria who were also Syrians. Yet Abraham became the father of the Hebrew nation by virtue of his call and covenant promises, not by a change in blood; he remained genetically a Syrian. Les notes that even though Scripture considers Abraham the father of the Jewish race and people often call him the first Jew, genetically Isaac was the first son of promise and the first real Jew by birth. Abraham came out of Ur of the Chaldees and then into the land of promise.