Here, Abu Hamid al-Ghazali aims to teach his readers firstly the theory of what is lawful and what is unlawful and how to deal with dubious or ambiguous issues, and secondly how to apply the knowledge they have gained to their everyday lives. The main support for this application, especially in matters that are unclear, is caution or prudence, and Ghazali explains the degrees of prudence necessary, beginning with the prudence of the upright and ending with the prudence of the saintly. Thus the sincere practice of what is lawful and desisting from what is unlawful become integrated into one’s spiritual life.