In the Mysteries of Charity and Its Important Elements (Kitab asrar al zakat wa-muhimatiha; book 5), and the Mysteries of Fasting and Its Important Elements (Kitab asrar al-iyyam wa-muhimatiha; book 6), of the forty books of the Revival of the Religious Sciences (Iya ulum al-din), Abu amid al-Ghazali explains the inner and outer meanings of charity and fasting, two pillars of worship for Muslims. These are two of the five books...