The Brethren of Purity (Ikhwān al-Ṣafā’) were a ninth-tenth century secret Shīʾite philosophical movement from Basra. They have a unique intertextual approach to interpreting the Qurʾān for their own philosophical worldview which sets the stage for how later Muslim mystics like Ibn ‘Arabī (d. 1240) will interpret the Qurʾān. They do not see the Qurʾān as a text that comments on esoteric, philosophic, or theurgic ideas and practices. Instead, they see the Qurʾān and philosophical texts (and practices) as direct reflections of each other. The Brethren saw Hermes (as Idrīs), Pythagoras, Socrates, Plotinus, Moses, Jesus, and Muhammad as all prophets of God. Therefore, they saw their texts as divine works. I argue that the Brethren of Purity’s mysticism is drawn from the Qurʾān, along with Greek works. They justify using these non-Qurʾānic sources by stating that these are sacred books. Therefore, it was easy for them to intertextually interpret the ḥadīth of the Prophet Muḥammad: “heaven (which they interpret as the Universal Soul) is in the sky and hell is on the earth” as heaven being the Qurʾānic Divine Pen. They believed that the Unwritten Tablet was the Neoplatonic Universal Intellect (possessor of the Qurʾānic Divine Forms). The Brethren of Purity are Hermetic mystics who seek spiritual intercession from secondary powers (such as the Shīʾite Imāms, angels, and stars) and use prayers from the Qurʾān (combined with magic and theurgy) to unite with the Universal Soul. They state that angels and good fiery spirits called jinn live in the realm of the Universal Soul and are “specifically chosen for their knowledge of the intellectual sciences, philosophical and lordly opinions, and definitive proofs.” The good jinn listen to Qurʾānic injunctions to “follow [divine] commands and prohibitions.” The Brethren state that human beings must seek the help of the angels and jinn, and not simply expect them to help them without a call. Virtually every paragraph of the treatises of the Brethren begin with the following phrase “Know Oh Brother, may God provide you and us with a spirit from Him.” The Brethren’s invocation for a helper spirit from God is reminiscent of how the servant would call for help from God in the Qurʾān. But also similar to how Socrates begins the Timaeus. The Brethren literally ask God for a spirit come down to earth, and teach them how to understand all fifty-one sciences they wrote on correctly.