Al-Ghazali - The Marvels of the Heart

This is a classic Sufi manual on the 'science of the heart.'  For Sufis, the 'heart' is more than a piece of flesh, it is the seat of the soul, and holds the key to the intimate relationship which exists between soul and body.
 
Each heart, according to this traditional wisdom accumulated over centuries of spiritual practice and experience, possesses four qualities: predatory, animal, demonic, and divine. The latter represents our true origin and potential, and by use of the intelligence and spiritual practices enabled by God's grace, we may restore equilibrium to our inner core. As the Koran says: 'By the remembrance of God do hearts find peace.'
 
Ghazali uses a series of traditional Sufi teaching stories to illustrate the theme of the heart as a mirror. The light of the divine sun can only shine in the heart when the seeker recalls the Prophet's teaching that 'everything has a polish, and the polish of hearts is the remembrance of God.' Bad character traits, acquired through faulty upbringing, are like 'a smoke which clouds the heart's mirror'; this is the 'heart's rust' mentioned in the Koran. But the one who has polished his heart is made luminous by God's light, and brings that light to others, which is the quality of sainthood.

Abu Hamid al-Ghazali (d.1111), a native of Central Asia, was the best-known jurist, theologian and mystic of medieval Islam. Himself a teacher of Sufi initiates, he recorded his practical teaching in his great work, the 'Ihya' 'Ulum al-Din' ('Revival of the Sciences of Religion'), from which the present work is taken.