False Prophets and Ravening Wolves. Biblical Exegesis as a Tool against Heretics in Jacques Fournier’s Postilla on Matthew

Exegetical texts have rarely been regarded as historical instances of ideas about heterodoxy: scholars who have explored the relations between orthodoxy and heresies in medieval Europe have shown a surprising lack of interest in such sources. This article investigates the role played by biblical studies in the fight against heretics in the late Middle Ages. At the core of the inquiry is a monumental and unpublished commentary on the Gospel of Matthew composed by the inquisitor, cardinaltheologian, and eventually Pope Jacques Fournier/Benedict XII (ca. 1284-1342) in the 1320s-1330s. Fournier's commentary, written during the pontificate of John XXII in a context of vibrant theological disputes, houses the author's most complete reflection on the nature of heresy and provides a theoretical validation of the ecclesiastical procedures followed against heretics, stating the necessity of their physical extermination. As an exegetical text which tackles an in-depth analysis of the category of "haeretici," the commentary provides an interesting trait d'union between the theological and judicial sides of anti-heretical fight, shedding new light on the variety of Fournier's textual approaches to heresy, both as an inquisitor and as a theologian. The study of the Bible and the judicial quest undertaken in ecclesiastical courts appear to be manifestations of a complementary effort displayed by the Catholic Church in the defense of orthodoxy: next to the judicial work of inquisitors, the endeavor of biblical exegetes was consciously regarded as an essential component in the fight against heresy.