The study by Michael Cox illuminates how Deuteronomy serves as a document of community building by highlighting the social boundaries that the book provides. To answer the arising question why these forms of behavior are so valued in the vision of Deuteronomy, Cox discusses the following two-part thesis: The purification formula of Deuteronomy (eleven occurrences in 13:6; 17:7, 12; 19:13, 19; 21:9; 21:21; 22:21, 22, 24; 24:7) clarifies the group-boundaries of the community envisioned in Deuteronomy. These boundaries are then used by later authors to evaluate subsequent communities. By reading Deuteronomy in its final form as a community-building document, Cox explores group formation in general and the more specific phenomenon of the exclusion of members from the group, which by insiders is a significant method to establish and enforce ideological norms. He argues that Deuteronomy’s axiomatic claim – found in the Shema, 6:4–5 – provides the ideological foundation for evaluating the particular behaviors that were marked out in the social landscape by the purification cases. Deuteronomy I is intended to be read and used by later communities. An exploration of Psalm 78 and 1 Corinthians 5, both of which allude to these purification cases, shows how later canonical authors evaluate their own communities based on Deuteronomy’s social vision.