Rather, Paul sees all human beings as one, part of his conception of the Christian world: “For we were all baptized by one Spirit into one body — whether Jews or Greeks, slave or free — and we were all given the one Spirit to drink” (1 Corinthians 12:13). This new unity is radical and transforming: when an individual, regardless of who he or she was comes to accept Christ he or she can say: “Therefore, if anyone is in Christ, he is a new creation; the old has gone, the new has come! (2 Corinthians 5:17). Paul believes external social roles and identities like keeping to Jewish Mosaic law or marriage laws are relatively unimportant — the real change comes from within the believer, and enables him to shine with Christs light in his or her new identity. Changes in specific ritual actions are not as significant, because they do not reflect a true change of heart.
This is what was so radical and threatening about Christianity vs. paganism. While paganism stressed the need for observing certain physical ritual acts, such as sacrificing to the gods, or honoring the god Caesar, Christianity advocated a more humble and personal form of transformation that did not require wealth, obedience to a leader, or membership in a social, economic, or natural order.
Of course, a Christian did not leave society entirely. But while still participating in earthly life, a Christian was able to feel a sense of transformation that enabled his or her social roles to be experienced in a new fashion. A believer today might feel a new birth in Christ, and still carry on in his obligations as a father and provider for his family. In fact, Paul would stress that the convert ought to do so, rather than abandoning his previous commitments. But with a new life in Christ, the believers duties are infused with a new sense of importance and love, and the believer can become a better father and a more ethical individual, because of the personal rebirth in Christ he has experienced in his heart.