Section II: Reasons for Istinja’

Firstly: Najas exiting urine and faeces
It is wajib to perform istinja’ or istijmar from urine and faeces exiting the body. This is the position of the majority: the most common opinion among the Malikis, Shafi`is, and Hanbalis. Pre-seminal Fluid (Madhy) [51] Madhy: a fine, viscous fluid that exits from the penis when aroused.
- Ruling of istinja’ from pre-seminal fluid
It is wajib to perform istinja’ from pre-seminal fluid, and this is the position of the majority: Malikis, Shafi`is, and Hanbalis.
- What must be done when performing istinja’ from pre-seminal fluid
During istinja’ from pre-seminal fluid, it is necessary to wash the point of exit and any affected areas that have been in contact with it. This is the position of the majority of scholars.
- Ruling of istijmar from pre-seminal fluid
Scholars have differed over the ruling of performing istijmar from pre-seminal fluid according to two views:
First: It is that istijmar with stones suffices as a process of purification from pre-seminal fluid, and this is the position of Malikis, an opinion among the Shafi`is, and the choice of Ibn Taymiyyah.
Second: It is that water is necessary for purification and istijmar does not suffice, and this is the position of Malikis, the correct opinion among Shafi`is, and the choice of Ibn Hazm the Zahiri.

- Wady:  [52] Wady is a viscous liquid which sometimes exits from the penis post-urination.
It is wajib to perform istinja’ or istijmar from wady, and this is the position of the majority: Malikis, Shafi`is, and Hanbalis.
- Blood and Puss:
It is wajib to perform istinja’ from blood that exits from the private parts of a woman like istihadah [53] Istihadah is when vaginal bleeding persists after the habitual menstruation days a woman is used to. It exits from the vagina and not the womb, and its sign is that it does not have a distinct scent.
- Blood, or from the anal passage like haemorrhoids:
This is the position of the majority: Malikis, Shafi`is, and Hanbalis.

Secondly: A pure substance exiting wind
It is not necessary to perform istinja’ due to passing wind, and this is by agreement of the four schools of jurisprudence. 
- A Pure, Dry Substance Exiting:
It is not necessary to perform istinja’ from the emission of a pure, dry substance that will not stain, like stones. This is the position of the majority: Hanafis, Malikis, Shafi`is, and some Hanbalis.

Thirdly: Persistent hadath obligation of precautionary measures against najasah from one with persistent hadath
It is wajib for those in a state of persistent hadath to take the appropriate means against the involuntary exiting of their respective najasah, [54] A woman experiencing istihadah for instance would cover her private part with a cloth or dressing, and one with urinary incontinence or abundant involuntary pre-seminal fluid would do the same with their penis, making sure as much of the najasah has left their body prior to purification. If it were something that cannot be pressed or squeezed like a cut on a flat bit of skin, or a varicose vein that cannot be drained, then the person afflicted with this would pray according to their situation. and this is the position of the majority, Hanafis, Shafi`is, and Hanbalis. 
- Istinja’ at time of each prayer entering:
Whoever has a permanent form of hadath, then he does not have to perform istinja’ for each individual prayer he prays. This is the Maliki position, an opinion among the Shafi`is, a narration from Ahmad, and the choice of Ibn Rajab. Sleep
Istinja’ from sleep is not legally mandated, and this is by agreement of the four schools of jurisprudence.

Fourthly: Ruling of the order between istinja’ and ablution
Ablution is valid before istinja’, [55] But it is better to perform istinja’ before ablution. and this is the position of the majority: Hanafis, [56] Istinja’ is one of the sunnah acts of ablution for the Hanafis. Malikis, Shafi`is, and a narration from Ahmad.