"There are two things that I memorized from the Messenger of Allah, who said: 'Allah has decreed proficiency in all things, so when you kill, kill well, and when you slaughter, slaughter well. Let one of you sharpen his blade and spare suffering to the animal he slaughters.'" (Sahih)  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ إِنَّ اللَّهَ كَتَبَ الإِحْسَانَ عَلَى كُلِّ شَىْءٍ فَإِذَا قَتَلْتُمْ فَأَحْسِنُوا الْقِتْلَةَ وَإِذَا ذَبَحْتُمْ فَأَحْسِنُوا الذِّبْحَةَ وَلْيُحِدَّ أَحَدُكُمْ شَفْرَتَهُ وَلْيُرِحْ ذَبِيحَتَهُ