The early modern Muslim world witnessed unparalleled development in theological discussion, of which the problem of evil is a part. This paper aims to uncover a new discourse on the problem of evil in the Ottoman period, by examining the eleventh/ seventeenth-century polymath ʿAbd al-Ghanī al-Nābulusī’s (d. 1143/1731) synthetic theology of evil. More specifically, the study will analyze the way al-Nābulusī discusses the issue of faith (īmān) and disbelief (kufr) in his Ashʿarī kalām and Akbarian Sufism. Looking first at al-Nābulusī’s kalām metaphysics of īmān and kufr and then his mystical metaphysics, the paper corroborates how between the two sciences, there is a coherent logic in al-Nābulusī’s concordia theology.