Sahih Muslim 1290 a
The Book of Pilgrimage
It is recommended to send the weak among women and others ahead from Al-Muzdalifah to Mina at the end of the night, before it gets crowded, but it is recommended for others to stay there until they have prayed Subh in Al-Muzdalifah
'A'isha (Allah be pleased with her) reported: Sauda (the wife of the Prophet) who was bulky sought the permission of Allah's Messenger (ﷺ) on the night of Muzdalifa to move from (that place) ahead of him and before the multitude (set forth). He (Allah's Messenger (ﷺ) ) gave her the permission. So she set forth before his (Prophet's) departure. But we stayed there until it was dawn and we moved on, when he departed. And if I were to seek the permission of Allah's Messenger (ﷺ) . (ﷺ) as Sauda had sought permission, I could have also gone with his permission and it would have been better for me than that for which I was happy.