In the context of the much-debated 'return of religion', this paper argues that Heidegger’s concept of responsibility for oneself, including the idea of fallenness, owes itself chiefly to Augustine and his discussion of sin and temptation. The crucial difference is that Heidegger conceives the process of an agent’s singularization as taking place in confrontation with one’s dying, the dying that opens up possibilities for an agent, rather than with the personal loving god of Augustine’s Confessions.