an impurity has entered is, in his view, impure, even if none of its characteristics has changed, unless it is a vast body of water so extensive that no person can set both its ends in motion. Al-Shāfiʿī defines suitable water, when its quantity is less than two qullahs, as water into which no impurity has entered; when its quantity exceeds two qullahs, it is water none of whose characteristics has been changed by a pure or impure substance that has entered it.

Section
Distinguishing the Obligatory Acts of Ablution from Its Sunnah Practices and Recommended Acts

We have already mentioned that ablution prescribed by Islamic law comprises obligatory acts, Sunnah practices and recommended acts. There are eight obligatory requirements of ablution. Four are agreed upon by the scholars: those explicitly stated by Allah Most High—washing the face and arms, wiping the head, and washing the feet. Two are agreed upon within the school: intention, and plain water none of whose characteristics has been changed by a pure or impure substance that has entered it. Two are disputed within the school: continuity between the acts and their prescribed order.

There are three positions concerning continuity. The first is that it is obligatory in all cases; this is the position of ʿAbd al-ʿAzīz ibn Abī Salamah. The second is that it is a Sunnah practice in all cases; this is the well-known position within the school. The third is that it is obligatory for the parts that are washed and a Sunnah practice for those that are wiped. This is the position reported by Mutarrif and Ibn al-Mājishūn from Mālik, and it is the weakest of the three positions.

According to the position that continuity is obligatory, anyone who interrupts ablution, whether forgetfully or deliberately, must repeat both the ablution and the prayer. According to the position that it is a Sunnah practice, nothing is required of someone who interrupts it forgetfully. If someone interrupts it deliberately, however, there are two positions. The first is that nothing is required of him; this is the position of Muhammad ibn ʿAbd al-Hakam. The second is that he must repeat both the ablution and the prayer for deliberately omitting one of its Sunnah practices, since he is acting like someone who treats worship frivolously and carelessly. This is Ibn al-Qāsim’s position. Some of our scholars express his position on continuity by saying that it is obligatory when one remembers, but that the obligation is waived through forgetfulness, as with speaking during prayer.

According to the first interpretation, if someone’s water is spilled during ablution, and he began his ablution with water