Fifteen Letters (Khamsata 'Ashara Maktuban)

Originally written in Persian, the fifteen letters were translated into Arabic by 'Ali Husamu'd-din al-Muttaqi (the Devout), who said of them, "these letters comprise nuggets of wisdom and spiritual counsel, couched in various forms of allegory, metaphor, paraphrase and quotation, including approximately two hundred and seventy-five Qur'anic verses. They also contain allusions to the experiences [adhwaq] and spiritual states [halat] of the Sufis (may Allah's good pleasure be conferred upon them all).