Is staying overnight (Mabit) at Muzdalifah obligatory, and what is the ruling for those who fail to do so?
Chapter on Ransom (Fidyah) and Penalty for Hunting
Al-Mughni
Book of Hajj
Primary text
Staying overnight at Muzdalifah is an obligation, and neglecting it necessitates a sacrifice (Dam), whether the omission was intentional, by mistake, or due to ignorance, because it constitutes leaving a ritual where forgetfulness treats the non-existent act as non-existent. This is the established madhab.
Supporting text
A concession is granted for the keepers of the pilgrims' water supply (Saqayyat al-Hujjaj) and camel herders to omit staying overnight because the Prophet, peace be upon him, granted a concession to the herders, and Al-'Abbas was permitted to stay over due to his duty of watering the pilgrims, as they face hardship in staying overnight while needing to guard their animals and water the pilgrims. A narration from Ahmad suggests that staying overnight at Muzdalifah is not obligatory and no penalty is due for omitting it.