Allah has prescribed excellence in everything

On the authority of Abu Ya'la Shaddad ibn Aws (may Allah be pleased with him), that the Messenger of Allah (may Allah bless him and grant him peace) said: "Allah has prescribed excellence in all things. So if you kill, kill well; and if you slaughter, slaughter well. Let each of you sharpen his blade and spare the animal he slaughters."

Related by Muslim.

[Muslim 1955]