It is generally believed that the commentary of the Qur’ān (tafsīr) by the medieval Muslim theologian Muḥammad ibn Jarīr al-Ṭabarī (839–923), who is the first systematizer of classical Qur’ānic exegesis, “Jā mi‘ al-bayā n ‘an ta’wī l ay al-Qur’ā n” (“The Comprehensive Exposition of the Interpretation of the Qur’ān”) definitely belongs to the genre of commentary based on traditions (tafsīr bi-l-ma’thūr), which is usually opposed to the genre of rationalistic interpretations (tafsīr bi-r-ra’y), rejected by a number of literalist movements of Islam. However, the analysis carried out in this study shows that Ṭabarī not only cites the traditions of the “ancient fathers of the Ummah”, while often representing different opinions, but also expresses his own point of view, based in most cases on the basis of linguistic analysis. The exegetical formula “tradition + language” formulated by him, where the latter element is decisive, is a peculiar combination of the traditional with the rational. This approach of “the lead of the Mufassiers”, among other things, opens up wide opportunities for future generations to reveal modern interpretations of the Qur’ānic text.