Salim bin 'Abdullah bin 'Umar سالم بن عبد الله بن عمر بن الخطاب · The Book of ad-Dahaya (Sacrifices)

"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 )