عَنْ شَدَّادِ بْنِ أَوْسٍ رَضِيَ اللَّهُ عَنْهُ قَالَ ثِنْتَانِ حَفِظْتُهُمَا عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِنَّ اللَّهَ عَزَّ وَجَلَّ كَتَبَ الْإِحْسَانَ عَلَى كُلِّ شَيْءٍ فَإِذَا قَتَلْتُمْ فَأَحْسِنُوا الْقِتْلَةَ وَإِذَا ذَبَحْتُمْ فَأَحْسِنُوا الذَّبْحَ وَلْيُحِدَّ أَحَدُكُمْ شَفْرَتَهُ وَلْيُرِحْ ذَبِيحَتَهُ
It is narrated from Sayyiduna Shaddad bin Aws (may Allah be pleased with him), he says: I have remembered two things from the Noble Prophet (peace and blessings be upon him), he (peace and blessings be upon him) said: Allah Almighty has made excellence obligatory in everything, so when you kill (out of necessity), kill in a good manner, and when you slaughter, slaughter in a good manner. Sharpen your knife and give comfort to the animal being slaughtered.