Paul not only tells us who he is; he tells us who he is not. He says he is not a Gentile sinner—not simply not a Gentile; he is not a Gentile sinner. By so doing, Paul makes clear to us that the terminology of Jew and Gentile does not merely refer to one’s ethnic or cultural heritage; the terms Jew and Gentile also refer to one’s morality and one’s disposition vis-à-vis God.
