One of the marks of sin is our disunity, our categorizing, our domination over one another. But remember, this is after the Fall, after sin. For centuries groups of people have been jockeying for position at the expense of others. Whites have subordinated people of color. That is and always will be sin.
Full redemption is both personal and social.
Paul, for most of his adult life, had been a zealous Jew. Paul, the man who became the great missionary and apostle, spent most of his life as a privileged, educated, haughty, religious man who accepted as fact the social realities of his day. He assumed that Jews were superior to Greeks, free citizens were more worthy than slaves, and men were unquestionably better than women. But Christ seared his world view with the truth on the road to Damascus. His whole world view changed.