كتاب الصيد والذبائح وما يؤكل من الحيوان
34
The Book of Hunting, Slaughter, and what may be Eaten
(5)
Chapter: The prohibition of eating the meat of domesticated donkeys
(5)
باب تَحْرِيمِ أَكْلِ لَحْمِ الْحُمُرِ الإِنْسِيَّةِ ‏‏
Sahih Muslim 1940 b

Anas b. Malik reported:

When it was the Day of Khaibar a visitor came and said: Messenger of Allah, the asses have been eaten. Then another came and said: Messenger of Allah, the asses are being destroyed. Then Allah's Messenger (ﷺ) commanded Abu Talha to make an announcement that Allah and His Messenger have prohibited you (from eating) of the flesh of (domestic) asses, for these are loathsome or impure. He (the narrator) said: The earthein pots were turned over along with what was in them.
حَدَّثَنَا مُحَمَّدُ بْنُ مِنْهَالٍ الضَّرِيرُ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، حَدَّثَنَا هِشَامُ بْنُ حَسَّانَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ لَمَّا كَانَ يَوْمُ خَيْبَرَ جَاءَ جَاءٍ فَقَالَ يَا رَسُولَ اللَّهِ أُكِلَتِ الْحُمُرُ ‏.‏ ثُمَّ جَاءَ آخَرُ فَقَالَ يَا رَسُولَ اللَّهِ أُفْنِيَتِ الْحُمُرُ فَأَمَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم أَبَا طَلْحَةَ فَنَادَى إِنَّ اللَّهَ وَرَسُولَهُ يَنْهَيَانِكُمْ عَنْ لُحُومِ الْحُمُرِ فَإِنَّهَا رِجْسٌ أَوْ نَجِسٌ ‏.‏ قَالَ فَأُكْفِئَتِ الْقُدُورُ بِمَا فِيهَا ‏.‏
Reference : Sahih Muslim 1940 b
In-book reference : Book 34, Hadith 50
USC-MSA web (English) reference : Book 21, Hadith 4778
  (deprecated numbering scheme)