Scholars differed concerning a cat that eats a mouse or something similar and then laps from a small quantity of water. There are four views within the school of Ahmad and elsewhere.

One view holds that the water is pure without qualification. Another holds that it is impure until the cat’s mouth is known to be pure. A third holds that if the cat has been absent long enough to have encountered something that would purify its mouth, the water is pure; otherwise, it is not. These views are found within the schools of al-Shāfiʿī, Ahmad, and others. A fourth holds that if a long interval has elapsed, the water is pure, treating the cat’s saliva as purifying its mouth on grounds of need. This is the view of some followers of Abū Hanīfah and Ahmad, and it is the strongest view. Allah knows best.

He was asked:

A man immersed his hand in water before washing it after waking from a night’s sleep. Does this water remain suitable for ritual purification? What is the wisdom behind washing the hand if it remained pure overnight? Please give us a ruling, and may you be rewarded.

He replied:

Praise be to Allah. Whether the water thereby becomes used water that may not be used for ablution is a well-known matter of disagreement. Two positions are reported from Ahmad, each preferred by a group of his followers. The prohibition was preferred by Abū Bakr, al-Qādī, and most of the latter’s followers. This is also reported from al-Hasan and others. The second position is that the water does not become used water. This was preferred by al-Khiraqī, Abū Muhammad, and others, and it is