In his works of history and tafsīr, Abū’l-Fidāʾ Ismāʿīl b. ʿUmar b. Kathīr (d. 773/1373) argues in favor of his teacher, Ibn Taymiyya’s, program of reform, what Walid Saleh terms the older man’s “radical hermeneutics.” Ibn Kathīr argues in favor of the strict reliance upon the Qurʾān and authoritative ḥadīth – especially those found in the Six Books and Aḥmad b. Ḥanbal’s Musnad. And yet, as Saleh points out, Ibn Kathīr’s Tafsīr al-Qurʾān al-Aẓīm does not strictly follow this methodology. Instead, he focuses on philology and an encyclopedic approach that aligns him more closely with one of his major sources, the tenth century Baghdadi scholar, al-Ṭabarī. I argue that Ibn Kathīr’s failure to follow Ibn Taymiyya’s program extends to his sīra of the Prophet Muḥammad as well (as found in his larger work of history, Al-Bidāya wa’l-Nihāya). To this end, I compare Ibn Kathīr’s treatment of two events in the life of Muḥammad, the story of a letter sent by one of Muḥammad’s Companions to warn the Meccans of his impending attack and the story of the attempted assassination of Muḥammad by ʿĀmir b. al-Tufayl and Arbad b. Qays and its aftermath, and the Qurʾān verses associated with them (Q. 60:1-4, 13:9-13) across the genres of sīra and tafsīr. In both cases, Ibn Kathīr does use authoritative reports and Qurʾān quotations. And yet, he also includes reports that are not authoritative (although he is careful to point out their flaws), and puts forward his own interpretation of events without any supporting evidence whatsoever. But why would Ibn Kathīr fail to follow Ibn Taymiyya’s and his own professed methodology, one that he vehemently and quite defensively supports in both works? I propose that Ibn Kathīr uses questionable sources and includes his own interpretation as a sort of pragmatic compromise between Ibn Taymiyya’s “radical hermeneutics” and his own need to insure that his audience receives the correct interpretation of the significance of these events in the life of Muḥammad and the explanation of the Qurʾān. Thus, Ibn Kathīr’s works should not be viewed as a reflection of the stultification of the Islamic intellectual tradition, as they often are by modern scholars, but rather as a reflection of his attempt to insure that the Muslim community was properly guided during a period of immense change, even if it meant compromising his methodological principles.