كتاب الحج
15  
The Book of Pilgrimage
(37)
Chapter: It is recommended to enter Makkah from the Upper Mountain Pass and to leave from the Lower Mountain Pass; Entering a city via a route different than the one by which you leave it
(37)
باب اسْتِحْبَابِ دُخُولِ مَكَّةَ مِنَ الثَّنِيَّةِ الْعُلْيَا وَالْخُرُوجِ مِنْهَا مِنَ الثَّنِيَّةِ السُّفْلَى وَدُخُولِ بَلْدَةٍ مِنْ طَرِيقٍ غَيْرِ الَّتِي خَرَجَ مِنْهَا
Sahih Muslim 1258 a

'A'isha (Allah be pleased with her) reported that when Allah's Messenger may peace be upon him) came to Mecca he entered from its upper side and came out from its lower side.

حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ أَبِي عُمَرَ، جَمِيعًا عَنِ ابْنِ عُيَيْنَةَ، - قَالَ ابْنُ الْمُثَنَّى حَدَّثَنَا سُفْيَانُ، - عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم لَمَّا جَاءَ إِلَى مَكَّةَ دَخَلَهَا مِنْ أَعْلاَهَا وَخَرَجَ مِنْ أَسْفَلِهَا ‏.‏
Reference : Sahih Muslim 1258a
In-book reference : Book 15, Hadith 248
USC-MSA web (English) reference : Book 7, Hadith 2887
  (deprecated numbering scheme)