Several Qur’anic verses explicitly or implicitly indicate a division of sins into “major” (kabaʾir) and “minor” (ṣaghaʾir). Among these, verse 31 of Surat al-Nisaʾ is of particular importance, as it not only references this dichotomy but also introduces the concept of takfir al-sayyiʾat, a notion closely intertwined with the broader issue of sin classification. Since the earliest stages of Qur’anic exegesis, these concepts have drawn sustained attention from exegetes, who have offered diverse interpretations regarding their scope and nature. Employing a descriptive–analytical method and a comparative approach, this study examines and analyzes the views of Fakhr al-Razi -representing the Ashʿari theological tradition- and ʿAllamah Ṭabaṭabaʾi-one of the most prominent contemporary Imami exegetes- on the notions of kabaʾir, ṣaghaʾir, and takfir al-sayyiʾat. Through a systematic comparison of their exegetical positions, the study seeks to identify the points of convergence and divergence between them, as well as the underlying factors contributing to these differences. The findings indicate that while Fakhr al-Razi and ʿAllamah Ṭabaṭabaʾi share certain commonalities -such as accepting the basic distinction between major and minor sins, agreeing or disagreeing with various interpretive opinions related to the verse, and occasionally employing similar lines of reasoning- each ultimately arrives at an independent and distinctive understanding of the verse’s key concepts. Moreover, notable differences emerge in areas such as whether the major sins have been explicitly determined by God, their respective approaches to the views of other theological schools -particularly the Muʿtazila- and the interpretive methodologies they apply in analyzing the verse.