كتاب الحج
15  
The Book of Pilgrimage
(38)
Chapter: It is recommended to stay overnight in Dhu Tuwa when intending to enter Makkah, and to perform Ghusl before entering it, and to enter it by day
(38)
باب اسْتِحْبَابِ الْمَبِيتِ بِذِي طَوًى عِنْدَ إِرَادَةِ دُخُولِ مَكَّةَ وَالاِغْتِسَالِ لِدُخُولِهَا نَهَارًا
Sahih Muslim 1259 c

Abdullah (b. 'Umar) reported that whenever Allah's Messenger (ﷺ) entered Mecca, he got down at Dhi Tuwa and spend the night there until he observed the dawn prayer. And Allah's Messenger (ﷺ) observed this prayer on a rough hillock, and not in the mosque which had been then built there, but to the lower side of it (the mosque) on a hillock.

وَحَدَّثَنَا مُحَمَّدُ بْنُ إِسْحَاقَ الْمُسَيَّبِيُّ، حَدَّثَنِي أَنَسٌ، - يَعْنِي ابْنَ عِيَاضٍ - عَنْ مُوسَى بْنِ عُقْبَةَ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ، حَدَّثَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَنْزِلُ بِذِي طَوًى وَيَبِيتُ بِهِ حَتَّى يُصَلِّيَ الصُّبْحَ حِينَ يَقْدَمُ مَكَّةَ وَمُصَلَّى رَسُولِ اللَّهِ صلى الله عليه وسلم ذَلِكَ عَلَى أَكَمَةٍ غَلِيظَةٍ لَيْسَ فِي الْمَسْجِدِ الَّذِي بُنِيَ ثَمَّ وَلَكِنْ أَسْفَلَ مِنْ ذَلِكَ عَلَى أَكَمَةٍ غَلِيظَةٍ ‏.‏
Reference : Sahih Muslim 1259c
In-book reference : Book 15, Hadith 252
USC-MSA web (English) reference : Book 7, Hadith 2891
  (deprecated numbering scheme)