Tyconius, a fourth-century Donatist, believed that the Bible showed the church as composed of two parts, the righteous and the sinners, who will be clearly separated only at the final judgment. This doctrine belongs to a shared Jewish and Christian tradition attested to in Romans, the third-century Christian Jewish Didascalia apostolorum, Tyconius’s Christian contemporaries in the East and the West, and talmudic and midrashic traditions attributed to fourth-century rabbis. Recognizing the exegetical tradition behind this doctrine brings a deeper understanding of it and its application to ecclesiology through the ages.