Why did God choose Abraham from the idolatrous world?
God chose Abraham because, out of a race saturated in idolatry and paganism, He found one man who still had a spark of faith or the ability to believe. Abraham was singled out for his capacity to believe, not because the world was righteous.
Les explains that in the roughly 400 years between Noah and Abraham, the Tower of Babel arose under Nimrod. There Satan, as the god of this world, instituted all pagan and mythological religions; every idolatrous religion began at Babel. By Abraham's time around 2000 B.C., the whole known human race was steeped in idolatry and mythology. Out of that saturated race, God found one man—Abraham—who still had a spark of faith or the ability to believe.