The Ihya Ulum al-Din is widely regarded as one of the great works of Muslim spirituality, and has, for centuries, been the widely read work in the Muslim world. It is divided into four parts each containing ten chapters. The first part deals with knowledge and the requirements of faith spiritual purity, prayer, charity, fasting, pilgrimage, recitation of the Qur'an. Part two concentrates mostly on people and society the manners relating to eating, marriage, earning a living, friendship, etc. Parts three and four are dedicated to the inner life of the soul and discuss first the vices that people must overcome in themselves and then the virtues that they must strive to achieve.