The 17th of the 42 hadiths gathered by Imam Yahya ibn Sharaf an-Nawawi in An-Nawawi's Forty Hadith, given below in the original Arabic with an English translation and its reference.
On the authority of Abu Ya’la Shaddad bin Aws (may Allah be pleased with him), that the Messenger of Allah (peace and blessings of Allah be upon him) said: Verily Allah has prescribed ihsan (proficiency, perfection) in all things. So if you kill then kill well; and if you slaughter, then slaughter well. Let each one of you sharpen his blade and let him spare suffering to the animal he slaughters.” [Muslim]
Sunni collections: text from the open hadith-api dataset. Al-Kafi: Arabic text, Muhammad Sarwar's translation and gradings from Thaqalayn.net via the Thaqalayn API. Hadith numbering follows those editions and can differ from a printed copy — check the Arabic against a trusted edition before relying on a reference.
