Sahih al-Bukhari 4417
Narrated Safwan bin Ya`la bin Umaiya:
that his father said, "I participated in Al-Usra (i.e. Tabuk) along with the Prophet." Ya`la added, "(My 
participation in) that Ghazwa was the best of my deeds to me." Ya`la said, "I had a laborer who 
quarrelled with somebody, and one of the two bit the hand of the other (`Ata', the sub-narrator, said, 
"Safwan told me who bit whom but I forgot it"), and the one who was bitten, pulled his hand out of 
the mouth of the biter, so one of the incisors of the biter was broken. So we came to the Prophet (ﷺ) and 
he considered the biter's claim as invalid (i.e. the biter did not get a recompense for his broken 
incisor). The Prophet (ﷺ) said, "Should he leave his hand in your mouth so that you might snap it as if it 
were in the mouth of a male camel to snap it?"
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، حَدَّثَنَا مُحَمَّدُ بْنُ بَكْرٍ، أَخْبَرَنَا ابْنُ جُرَيْجٍ، قَالَ سَمِعْتُ عَطَاءً، يُخْبِرُ قَالَ أَخْبَرَنِي صَفْوَانُ بْنُ يَعْلَى بْنِ أُمَيَّةَ، عَنْ أَبِيهِ، قَالَ غَزَوْتُ مَعَ النَّبِيِّ صلى الله عليه وسلم الْعُسْرَةَ قَالَ كَانَ يَعْلَى يَقُولُ تِلْكَ الْغَزْوَةُ أَوْثَقُ أَعْمَالِي عِنْدِي‏.‏ قَالَ عَطَاءٌ فَقَالَ صَفْوَانُ قَالَ يَعْلَى فَكَانَ لِي أَجِيرٌ فَقَاتَلَ إِنْسَانًا فَعَضَّ أَحَدُهُمَا يَدَ الآخَرِ، قَالَ عَطَاءٌ فَلَقَدْ أَخْبَرَنِي صَفْوَانُ أَيُّهُمَا عَضَّ الآخَرَ فَنَسِيتُهُ، قَالَ فَانْتَزَعَ الْمَعْضُوضُ يَدَهُ مِنْ فِي الْعَاضِّ، فَانْتَزَعَ إِحْدَى ثَنِيَّتَيْهِ، فَأَتَيَا النَّبِيَّ صلى الله عليه وسلم فَأَهْدَرَ ثَنِيَّتَهُ‏.‏ قَالَ عَطَاءٌ وَحَسِبْتُ أَنَّهُ قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏
"‏ أَفَيَدَعُ يَدَهُ فِي فِيكَ تَقْضَمُهَا، كَأَنَّهَا فِي فِي فَحْلٍ يَقْضَمُهَا ‏"‏‏.‏