What type of sleep necessitates washing the hands before performing Wudu?
Chapter on Siwak and the Sunnah of Wudu
Al-Mughni
Book of Purification
Primary text
Washing the hands before performing ablution (Wudu) is obligatory for any sleep that invalidates Wudu. This opinion is supported by the general indication found in the reports concerning sleep. The evidence for this generality supports the ruling that any instance of sleep requiring purification upon waking necessitates the hand washing.
Supporting text
Some scholars, such as Ibn Aqil, stipulate that the sleep must exceed half the night to be considered 'sleeping overnight' (ba'it). This is supported by the precedent that one departing Mina before the middle of the night is not considered to have stayed overnight there, unlike one who departs after midnight, for whom a penalty (damm) is required. However, this view is refuted by the case of one arriving at Muzdalifah after midnight; such a person is considered to have stayed overnight there even if their stay was less than half the night, yet no penalty is incumbent upon them.