كتاب الحج
15  
The Book of Pilgrimage
(20)
Chapter: All of Arafat is a place of standing
(20)
باب مَا جَاءَ أَنَّ عَرَفَةَ كُلَّهَا مَوْقِفٌ ‏
Sahih Muslim 1218 c

Jabir reported Allah's Messenger (May peace be upon him) as saying:

I have sacrificed (the animals) here, and the whole of Mini is a place for sacrifice; so sacrifice your animals at your places. 1 have stayed here (near these rocks), and the whole of Arafat is a place for stay. And I have stayed here (at Muzdalifa near Mash'ar al-Haram and the whole of Muzdalifa) is a place for stay (i. e. one is permitted to spend night in any part of it, as one likes).
حَدَّثَنَا عُمَرُ بْنُ حَفْصِ بْنِ غِيَاثٍ، حَدَّثَنَا أَبِي، عَنْ جَعْفَرٍ، حَدَّثَنِي أَبِي، عَنْ جَابِرٍ، فِي حَدِيثِهِ ذَلِكَ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ نَحَرْتُ هَا هُنَا وَمِنًى كُلُّهَا مَنْحَرٌ فَانْحَرُوا فِي رِحَالِكُمْ وَوَقَفْتُ هَا هُنَا وَعَرَفَةُ كُلُّهَا مَوْقِفٌ وَوَقَفْتُ هَا هُنَا وَجَمْعٌ كُلُّهَا مَوْقِفٌ ‏"‏ ‏.‏
Reference : Sahih Muslim 1218c
In-book reference : Book 15, Hadith 161
USC-MSA web (English) reference : Book 7, Hadith 2805
  (deprecated numbering scheme)