''Laṭā'if al-Isharat bi-Tafsīr al-Qur'ān'' is a famous work of al-Qushayri that is a complete commentary of the
Qur'an. He determined that there were four levels of meaning in the Qur'an. First, the
ibara which is the meaning of the text meant for the mass of believers. Second, the
ishara, only available to the spiritual elite and lying beyond the obvious verbal meaning. Third,
laṭā’if, subtleties in the text that were meant particularly for saints. And finally, the
ḥaqā’iq, which he said were only comprehensible to the
prophets. This text placed him among the elite of the Sufi mystics and is widely used as a standard of Sufi thought. His fame however, is due mostly to his
al-Risala al-Qushayriyya (or the
Epistle on Sufism). This text is essentially a reminder to the people of his era that Sufis had authentic ancestral tradition, as well as a defence of Sufism against the doubters that rose during that time of his life. Al-Qushayri repeatedly acknowledges his debt to, and admiration for, his Sufi master throughout his Risala. Daqqaq was instrumental in introducing Qushayri to another outstanding Sufi authority of Khurasan,
al-Sulami, who is quoted on almost every page of the Risala. It has sections where al-Qushayrī discusses the creed of the Sufis, mentions important and influential Sufis from the past, and establishes fundamentals of Sufi terminology, giving his own interpretation of those Sufi terms. Al-Qushayrī finally goes through specific practices of Sufism and the techniques of those practices. This text has been used by many Sufi saints in later times as a standard, as is obvious from the many translations into numerous languages. ==Legacy==