A Shi'ite theologian from Baghdad ,al-Shaykh al- Mufid was one of the most eminent scholars of Imami thought. His writings about 'Ali rely on transmitted traditions,and support the claim that 'Ali was the rightful successor, or khalifah, to Muhammad and the Imam of the Muslims. In his Kitab al-Irshad, al-Mufid reported some of 'Ali's sayings:

There is no life without religion and there is no death except through denial of the Certain Truth. Drink the sweet water of religion. It will wake you from the slumber of heedlessness. Beware of the hot, pestilential winds that bring destruction.

The world is the abode of truth for those who know it and the place of salvation for those who take their provisions from it. It is the place to which the revelation of God has been sent down and the market place...