The 52 Rasa’il (Epistles) of the Ikhwan al-Safa’ (Brethren of Purity) are known mainly for their encyclopaedic breadth, their eclecticism, their combination of religion and philosophy, their Neoplatonic substratum and their Ismaili overtones. However it is the Qur’anic quotations in the Rasa’il that provide them with a common thread which runs throughout their work. Even though the Rasa’il (written in Arabic in the 10th-11th centuries CE) are not a work of exegesis (tafsir) in the technical sense, they quote repeatedly from the Qur’an, using, explaining and expanding its semantic potentialities according to their own theological and philosophical notions. Thus, the Rasa’il practice a type of exegesis based on a particular hermeneutic vision of scripture which springs from a hierarchic conception of reality in which there are different levels in every sphere of existence: the structure of the Universe, the organisation of human society, the branches of knowledge and the meaning of scripture. This paper explores such a hermeneutic vision and its unifying role in the Rasa’il as a whole. The scriptural text is both a point of departure for the Rasa’il’s ideas and an authoritative instrument that supports and confirms their convictions. This paper also analyses the verses selected in the Rasa’il and the themes presented in those verses with the aim of improving our understanding of their interpretation of Islam and their contribution to religious and philosophical thought in general.