Sunan an-Nasai Book 45, Hadith 4768

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا سُفْيَانُ، عَنِ ابْنِ جُرَيْجٍ، عَنْ عَطَاءٍ، عَنْ صَفْوَانَ بْنِ يَعْلَى، عَنْ أَبِيهِ، قَالَ غَزَوْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي غَزْوَةِ تَبُوكَ فَاسْتَأْجَرْتُ أَجِيرًا فَقَاتَلَ أَجِيرِي رَجُلاً فَعَضَّ الآخَرُ فَسَقَطَتْ ثَنِيَّتُهُ فَأَتَى النَّبِيَّ صلى الله عليه وسلم فَذَكَرَ لَهُ فَأَهْدَرَهُ النَّبِيُّ صلى الله عليه وسلم ‏.‏

It was narrated from Safwan bin Ya'la that his father said:"I went on the campaign to Tabuk with the Messenger of Allah, and I hired a worker. My hired man fought with another man. The other one bit him, and his front tooth fell out. He went to the Prophet and told him about that, but the Prophet considered it to bin vain