كتاب المقدمات
1
The Book of Miscellany
Abu Ya'la Shaddad bin 'Aus (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "Verily Allah has prescribed Ihsan (kindness) for everything. So when you kill, you must make the killing in the best manner; when you slaughter, make your slaughter in the best manner. Let one of you sharpen his knife and give ease to his animal (in order to reduce his pain)."

[Muslim].

وعن أبى يعلى شداد بن أوس رضي الله عنه، عن رسول الله صلى الله عليه وسلم قال‏:‏ “إن الله كتب الإحسان على كل شئ، فإذا قتلتم فأحسنوا القتلة وإذا ذبحتم فأحسنوا الذبحة، وليحد أحدكم شفرته وليرح ذبيحته” ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏
Arabic/English book reference : Book 1, Hadith 640