In the following pages, I want to make these points: (1) In the ancient Roman world, worship was the key expression of “religion,” not beliefs and confessional formulas; (2) the key distinguishing feature that marked off Roman-era Judaism in the larger religious environment was its cultic exclusivity, the refusal to worship any deity other than the God of Israel; (3) this exclusivity involved refusal also to worship the adjutants of the biblical God, not simply foreign deities;