Why did God call Abram out of Babylon?
God called Abram out of Babylon because, after the Tower of Babel, the human race had reached a state where God could not continue dealing with them on the basis He had been using. So He chose one man, Abram, promising that a nation would come from him through whom He would consummate His plan of redemption.
Les explains that after the Tower of Babel the human race had reached a point where God could not continue dealing with them on the basis He had been using. So God did something totally different: He called out one man, Abram, from Ur in Babylon, and made the Abrahamic covenant with him. The promise was that out of Abram would come a nation of people, and through that nation God would consummate His whole plan of redemption. Abram comes on the scene around 2,000 B.C.; 500 years later Israel is a nation, having come out of Egypt under Moses and received the Law around 1,500 B.C. From Abraham until Christ, God dealt almost exclusively with the nation of Israel, setting the stage for His redemptive plan.