The letter to the Philippians is a work traditionally ascribed to the early Christian martyr Polycarp of Smyrna. The scholarly discussions surrounding the Polycarpian letter have concerned themselves with the question of the authenticity and unity of the text. In contrast, the present study aims at providing the first unifying account of the three major themes dealt with in the letter: sin, heresy and righteousness. In the Polycarpian letter, one encounters evidence of a way of conceiving of social and religious evil, in which objects of moral and doctrinal concern are judged equally regarding their disruptive force – particularly in relation to the longed-for uniformity of the Church. This way of blurring the distinction between different socially disruptive dogmas (“proto-heresies”) and habits (“proto-sins”) may be conceived of as characteristic of a pre-normative religious order.