Much has been written about ritual impurity in ancient Judaism, but the question of how the ancient Jews understood the relationship between defilement and sin has largely been ignored. This book offers the first systematic exploration of the important topic to be published in the last seventy years. Jonathan Klawans takes the results of current research on the Hebrew Bible and applies them to early Jewish and Christian groups. The Bible, he shows, considers the moral impurity generated by sin to be entirely distinct from (but no less real than) the ritual impurity generated by bodily function such as menstruation. Klawans then traces the relationship between ritual and moral impurity from early Jewish sects through the New Testament and the theology of Saint Paul and shows how Christian theology arrived at the point where the need for ritual purity was entirely rejected.