"I said: 'O Messenger of Allah we are going to meet the enemy tomorrow and we do not have any knives.' The Messenger of Allah said: "If the blood is shed and the name of Allah is mentioned, then eat, unless (it is slaughtered (with teeth or nails, and I will tell you about that. As for teeth, they are bones, and as for nails, they are the knives of the Ethiopians."' (Sahih )  

قُلْتُ يَا رَسُولَ اللَّهِ إِنَّا نَلْقَى الْعَدُوَّ غَدًا وَلَيْسَ مَعَنَا مُدًى فَقَالَ رَسُولُ اللَّهِ ﷺ مَا أَنْهَرَ الدَّمَ وَذُكِرَ اسْمُ اللَّهِ ﷻ فَكُلُوا مَا لَمْ يَكُنْ سِنًّا أَوْ ظُفْرًا وَسَأُحَدِّثُكُمْ عَنْ ذَلِكَ أَمَّا السِّنُّ فَعَظْمٌ وَأَمَّا الظُّفْرُ فَمُدَى الْحَبَشَةِ