Sunan an-Nasa'i, Book 43, Hadith 52 (In-Book) ⓘ
It was narrated that Shaddad bin Aws said: "The Messenger of Allah 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.'"
أَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ أَبُو عَمَّارٍ، قَالَ أَنْبَأَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَبِي الأَشْعَثِ الصَّنْعَانِيِّ، عَنْ شَدَّادِ بْنِ أَوْسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ اللَّهَ كَتَبَ الإِحْسَانَ عَلَى كُلِّ شَىْءٍ فَإِذَا قَتَلْتُمْ فَأَحْسِنُوا الْقِتْلَةَ وَإِذَا ذَبَحْتُمْ فَأَحْسِنُوا الذَّبْحَ وَلْيُحِدَّ أَحَدُكُمْ شَفْرَتَهُ وَلْيُرِحْ ذَبِيحَتَهُ " .
also referenced under: Hadith 4412 (Reference) & Volume 5, Book 43, Hadith 4417 (DarusSalam)