As a piece of writing, the Qur’an presents a number of challenges to its contemporary readers, beginning with the language. Despite the Qur’an referring to itself as a “clear” book (for example, in Q 5:15), it contains numerous words whose exact meanings are unknown and can only be inferred. Some of these words were puzzling even to the earliest interpreters of the Qur’an (Carter, 2017). These interpretative challenges are further compounded by the polysemy characteristic of Arabic: a typical feature of Arabic language is that its words frequently have broad semantic fields, with a single word carrying multiple meanings depending on the context (Hasan, 2013, pp. 106–107). Sometimes, disagreements over meaning may have dramatic consequences. In Sect. 2.1 , I told the story of Muhammad nominating his cousin Ali as the mawla for everyone for whom Muhammad himself had been a mawla. While the story is included in both Sunni and Shia sources, the sources interpret its key term differently. For the Shia, mawla denotes “master,” while for Sunnis, it denotes “friend.” Lexically, both interpretations are valid, but choosing one over the other has significant repercussions for one’s view of religious authority. While the story is not directly about the interpretation of the Qur’an, the polysemy it illustrates is also characteristic of Qur’anic vocabulary.