كتاب الذبائح
Read the English translation first, with the original Arabic directly underneath.
It was narrated from Shaddad bin Aws that the Messenger of Allah (ﷺ) said:
“Allah has prescribed Al-Ihsan (proficiency) in all things. So if you kill, then kill well, and if you slaughter, then slaughter well. Let one of you sharpen his blade and spare suffering to the animal he slaughters.”
إِنَّ اللَّهَ عَزَّ وَجَلَّ كَتَبَ الإِحْسَانَ عَلَى كُلِّ شَىْءٍ فَإِذَا قَتَلْتُمْ فَأَحْسِنُوا الْقِتْلَةَ وَإِذَا ذَبَحْتُمْ فَأَحْسِنُوا الذَّبْحَ وَلْيُحِدَّ أَحَدُكُمْ شَفْرَتَهُ وَلْيُرِحْ ذَبِيحَتَهُ