Each of them includes ten books. The first quarter book, Ihya’ Ulum al-Din, deals with acts of worship and duties, with a focus on the five pillars of Islam. The second quarter addresses a wide range of moral and social issues such as marriage, work ethics, table manners, and more. The third quarter deals with topics related to areas of weakness in the human soul, such as lust, anger, and scarcity. The last quarter includes virtues that save one from Hell, such as patience, remorse, and fear of God. It is a comprehensive book on morals, behavior, and Islamic sermons, which makes it distinct from everything else. His books are a comprehensive encyclopedia of everything that concerns the Muslim individual in matters of his religion, including belief, worship, treatment, and morals. It includes the interests of the individual and the group. His books are written in a practical way, aiming to rise from educational to behavioral level that pushes for a combination of work and science.