This study tests a widely held assumption in the diachronic study of the Hebrew Bible: that the narrative poetics used by the biblical authors are fully accessible to modern scholars, so they are rightfully empowered to determine a text’s unity, or lack thereof. To test whether the canons of narrative prose are relatively unchanged over time we need to find the work of a biblical exegete who lived in premodern times and yet was as committed to identifying fissures in the received text as are modern critical scholars. This study brings to light and examines just such an analysis: the biblical criticism of the eleventh-century Muslim theologian Ibn Hazm the Andalusian, whose critique of Hebrew Scriptures is more comprehensive than anything penned prior to the eighteenth century in Europe. The study concludes that, while Ibn Hazm identifies many of the types of inconsistencies that have been the basis for modern diachronic readings of the Hebrew Bible, he makes no mention of repetition or of narrative doubling as a sign of fissure in the text. Ibn Hazm worked in a climate in which repetition in literature was widely accepted. By contrast, nearly all modern scholars are heirs to the Aristotelian tradition of narrative unity laid out in his Poetics. Perforce, scholars cannot assume that ancient authors would necessarily have shared all of their notions of literary unity, which are demonstrably Aristotelian in nature.