Abū Sa‘īd al-Kharrāz, also known as "the Cobbler", was a pseudonym for Aḥmad bin ‘Īsā. He was a native of Baghdad. He had a devotion toward Sufi Islam, and so went to Egypt and resided piously by the Ka‘bah. His profession was that of a shoemaker, and he was a disciple of Muḥammad bin Manṣūr al-Ṭūsī. He associated with Dhū al-Nūn al-Miṣrī, al-Sarī al-Saqaṭī, Abū ‘Ubayd al-Baṣrī, and Bishr bin al-Ḥārith, and derived much spiritual instruction from them. To him is attributed the formulation of the mystical doctrine of passing away (from human attributes) and continuance (in God). He was the author of several books, some of which have survived. The date of his death is uncertain, but probably was between 279 A.H. (890 AD) and 286 (899). He was the first person to speak of the states of “passing-away” (fanā’) and “continuance” (baqā’) in the mystical sense, summing up his whole doctrine in these two terms.