This paper examines the origin of Barth's understanding of sin and grace in his reading of Dostoevsky in 1915. It is essentially the theological portrait of Sonya & Raskólnikov (Crime & Punishment) that regrounds Barth's understanding of sin and grace in an orthodox forensic model, which in turn develops into the mature doctrine we see in Die Kirchliche Dogmatik IV. The young Barth is exposed to many influences in his move away from nineteenth-century neo-Protestant liberal theology (characterized by a sociological-humanistic model of sin). Mediated by his theological colleague Eduard Thurneysen, Dostoevsky is one such influence amongst many. Barth's reading has a profound effect on him: sin becomes defined by and in relation to God –eritis sicut deus. This sublapsarian perspective can then be discerned in his seminal paper ‘Die Gerechtigkeit Gottes’, delivered within months of his reading of Crime & Punishment, particularly in the Dostoevsky motif of the Tower of Babel (this reading occurs five to seven years prior to the generally accepted period of the influence of Dostoevsky). Barth's understanding then develops through his study of Romans (Der Römerbrief ) and by rediscovering a traditional approach in the Reformed Confessions in the 1920s; however, it is his reading of Crime and Punishment that initiates this model of sin and grace.