Al-Shifa bi Ta'rif Huquq al-Mustafa,, of Qadi Ayyad is perhaps the most frequently used and commented upon handbook in which Muhammad's life, his qualities and his miracles are described in every detail. Generally known by its short title, ash-Shifa or al-Shifa, this work was so highly admired throughout the Muslim world that it soon acquired a sanctity of its own, for it is said, "If al-Shifa is found in a house, this house will not suffer any harm... when a sick person reads it or it is recited to him, Allah will restore his health."