كتاب الحج
15  
The Book of Pilgrimage
(49)
Chapter: 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
(49)
باب اسْتِحْبَابِ تَقْدِيمِ دَفْعِ الضَّعَفَةِ مِنَ النِّسَاءِ وَغَيْرِهِنَّ مِنْ مُزْدَلِفَةَ إِلَى مِنًى فِي أَوَاخِرِ اللَّيَالِي قَبْلَ زَحْمَةِ النَّاسِ وَاسْتِحْبَابِ الْمُكْثِ لِغَيْرِهِمْ حَتَّى يُصَلُّوا الصُّبْحَ بِمُزْدَلِفَةَ
Sahih Muslim 1293 a

Ibn 'Abbas reported:

Allah's Messenger (ﷺ) sent me from Muzdalifa ahead (of the caravan) along with the luggage or with the weak ones during (the latter part of the) night.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَقُتَيْبَةُ بْنُ سَعِيدٍ، جَمِيعًا عَنْ حَمَّادٍ، - قَالَ يَحْيَى أَخْبَرَنَا حَمَّادُ بْنُ زَيْدٍ، - عَنْ عُبَيْدِ اللَّهِ بْنِ أَبِي يَزِيدَ، قَالَ سَمِعْتُ ابْنَ عَبَّاسٍ، يَقُولُ بَعَثَنِي رَسُولُ اللَّهِ صلى الله عليه وسلم فِي الثَّقَلِ - أَوْ قَالَ فِي الضَّعَفَةِ - مِنْ جَمْعٍ بِلَيْلٍ ‏.‏
Reference : Sahih Muslim 1293a
In-book reference : Book 15, Hadith 330
USC-MSA web (English) reference : Book 7, Hadith 2965
  (deprecated numbering scheme)