Language:
كتاب الذبائح والصيد
72  
Hunting, Slaughtering
(22)
Chapter: The animals slaughtered by the people of the Scripture (Jews and Christians)
(22)
باب ذَبَائِحِ أَهْلِ الْكِتَابِ وَشُحُومِهَا مِنْ أَهْلِ الْحَرْبِ وَغَيْرِهِمْ
Sahih al-Bukhari 5508

Narrates `Abdullah bin Mughaffal:

While we were besieging the castle of Khaibar, Somebody threw a skin full of fat and I went ahead to take it, but on looking behind, I saw the Prophet (ﷺ) and I felt shy in his presence (and did not take it).

حَدَّثَنَا أَبُو الْوَلِيدِ، حَدَّثَنَا شُعْبَةُ، عَنْ حُمَيْدِ بْنِ هِلاَلٍ، عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ ـ رضى الله عنه ـ قَالَ كُنَّا مُحَاصِرِينَ قَصْرَ خَيْبَرَ، فَرَمَى إِنْسَانٌ بِجِرَابٍ فِيهِ شَحْمٌ، فَنَزَوْتُ لآخُذَهُ، فَالْتَفَتُّ فَإِذَا النَّبِيُّ صلى الله عليه وسلم فَاسْتَحْيَيْتُ مِنْهُ‏.

Reference : Sahih al-Bukhari 5508
In-book reference : Book 72, Hadith 34
USC-MSA web (English) reference : Vol. 7, Book 67, Hadith 416
  (deprecated numbering scheme)