كتاب الحج
15  
The Book of Pilgrimage
(85)
Chapter: The virtue of Al-Madinah and the Prophet's Prayer for it to be blessed. Its sanctity and the sanctity of its game and trees. The Boundaries of its sanctuary
(85)
باب فَضْلِ الْمَدِينَةِ وَدُعَاءِ النَّبِيِّ صلى الله عليه وسلم فِيهَا بِالْبَرَكَةِ وَبَيَانِ تَحْرِيمِها وَتَحْرِيمِ صَيْدِهَا وَشَجَرِهَا وَبَيَانِ حُدُودِ حَرَمِهَا
Sahih Muslim 1372 a

Abu Huraira (Allah be pleased with him) reported:

If I were to see deer grazing in Medina, I would have never molested them, for Allah's Messenger (ﷺ) has stated: There is between the two lava mountains a sacred territory.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّهُ كَانَ يَقُولُ لَوْ رَأَيْتُ الظِّبَاءَ تَرْتَعُ بِالْمَدِينَةِ مَا ذَعَرْتُهَا قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ مَا بَيْنَ لاَبَتَيْهَا حَرَامٌ ‏"‏ ‏.‏
Reference : Sahih Muslim 1372a
In-book reference : Book 15, Hadith 536
USC-MSA web (English) reference : Book 7, Hadith 3168
  (deprecated numbering scheme)