Know that the beginning of guidance is outward piety (taqwa) and the end of guidance is inward piety (ihsan). Only through piety is anything really achieved; only the pious are guided. Piety designates carrying out the commands of God most high and turning aside from what He prohibits, and thus has two parts.
In this book Imam Al-Ghazali sets out his ideal of how the religious man should order his life from hour to hour and day to day. The book is divided into three parts, obedience, avoidance of sins and the relationship between God and man and between His creation. This is one of Imam Al-Ghazali's final works, it embodies his life, spirituality and experience.