Kitab Ash-shifa bi ta'rif huquq al-Mustafa, (Healing by the recognition of the Rights of the Chosen one), of Qadi 'Iyad (d. 544H / 1149CE) is perhaps the most frequently used and commented upon handbook in which the Prophet's life, his qualities and his miracles are described in every detail. Generally known by its short title, Ash-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 Ash-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 s.w.t., will restore his health."
Qadi Iyad bin Mussa or Abu al-Fadl Ayyad bin Amer ben Mousssa bin Ayyad bin Mohammed bin Abdellah bin Mussa bin Ayyad al-Yahsobi al-Sabti (1083 - 1149), . Al-Yahobsi refers to Yahob a region in Jemen. Qadi Ayyad was born in Gibraltar. He was a high judge (kadi) in Grenada. He headed a revolt against the coming of the Almohades to Sebta, but lost and was banished to Tadla and later Marrakech. He was a pupil of Abu Abdullah bin Issa, of Imam Abu Abdullah bin Hamdine, of Abu Al Hassan bin Siradj and of imam Abu Al walid Ibn Rushd. As the great imam of Sebta, Ayad ben Musa was apointed Qadi of Grenada.
He was one of the most famous scholars of Maliki law. Qadi Ayyad bin Moussa is one of the seven saints of Marrakesh and is buried near Bab Aïlen. His main work is called Al-Shifa. The university of Marrakech (Cadi Ayyad) was named after him.