A comprehensive discussion of the principles of this (type of) worship (^ibadd) is covered in five chapters. Chapter 1 relates to the evidence of its obligation— on whom it is obligatory and when; Chapter 2 is about the identification of its acts; Chapter 3 is about the identification of that with which it is performed, that is, water; Chapter 4 is about the identification of factors nullifying it; and Chapter 5 is about the identification of things with which it can be performed.

23 Impurity (najdsa) is divided by the jurists into two kinds: actual (haqtqiya) and technical or legal (hukmiya). The term hadath is applied to legal or technical impurity, while khatyth to actual impurity. Hadath may be minor, which is removed through ablution, or it may be major (sexual defilement and menstruation) and is removed through bathing (gAws/). Similarly, actual najdsa may be heavy (mughallaza) or light (mvkhaffafa).

24 The term wad# is also referred to as the minor (sughra) ablution, while the term ghusl is referred to as the major (kubrd) ablution.