Musnad Ishaq

Benefits:
It is to depart from Muzdalifah towards Mina after the Fajr prayer but before sunrise. As narrated by ‘Amr ibn Maymun, when Sayyiduna ‘Umar radi Allahu anhu performed the Fajr prayer at Muzdalifah, I was present there. After the prayer, he stayed and said: The polytheists (in the days of ignorance) would not leave from here before sunrise. They used to say: O Thabir! (Thabir is the name of a mountain that lies to the left on the way to Mina) shine forth. The Noble Prophet sallallahu alayhi wa sallam opposed the polytheists and departed from there before sunrise. (Bukhari, no. 684; Sunan Abi Dawud, no. 1938)

However, there is no harm if weak children, the elderly, the sick, and women, etc., do not spend the entire night; they may proceed from Muzdalifah towards Mina after half the night has passed, as is established from the aforementioned ahadith. In another hadith, Sayyidah ‘A’ishah radi Allahu anha narrates: Sayyidah Sawdah radi Allahu anha was a heavy (of greater weight) woman. For this reason, she sought permission from the Messenger of Allah sallallahu alayhi wa sallam to depart from Muzdalifah (to Mina) during the night, and he sallallahu alayhi wa sallam granted her permission. (Bukhari, no. 1680; Muslim, no. 1290)