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.