It is mentioned in Faslul Khitab that at the time of sunrise he used to go into a prostration for the Creator and he used to so much prolong this prostration that it extended upto noontime. Due to intensive worship he had become so lean and emaciated that people barely recognized him. It seemed as if only a white cloth was lying on the prayer mat. Seeing the level of his worship, once Harun Rashid said: You are the monk and the pious one of Bani Hashim.