Sunan an-Nasa'i 4413
سنن النسائي#4413Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ رَافِعٍ، قَالَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَنْبَأَنَا مَعْمَرٌ، عَنْ أَيُّوبَ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَبِي الأَشْعَثِ، عَنْ شَدَّادِ بْنِ أَوْسٍ، قَالَ سَمِعْتُ مِنَ النَّبِيِّ، صلى الله عليه وسلم اثْنَتَيْنِ فَقَالَ " إِنَّ اللَّهَ عَزَّ وَجَلَّ كَتَبَ الإِحْسَانَ عَلَى كُلِّ شَىْءٍ فَإِذَا قَتَلْتُمْ فَأَحْسِنُوا الْقِتْلَةَ وَإِذَا ذَبَحْتُمْ فَأَحْسِنُوا الذَّبْحَ وَلْيُحِدَّ أَحَدُكُمْ شَفْرَتَهُ ثُمَّ لِيُرِحْ ذَبِيحَتَهُ " .
It was narrated that Shadad bin Aws said:"I heard two things from the Messenger of Allah He said 'Allah, the Mighty and Sublime, ahs 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 spear suffering to the animal he slaughter."" (Sahih)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 43:53