Verily Allah has prescribed Ihsan (proficiency, perfection) in all things
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]
The rule of Ihsan in the Islamic law is a constitutive basis on which all the rulings and moral principles are based. It is associated with justice, loyalty and mercy
The Prophet (peace and blessings of Allah be upon him) started talking to the believers in this commandment, which is a wonderful example of applying Ihsan in every work one does, even if this act is apparently cruel, or when roughness is supposed to prevail.
The expression: "Allah has written Ihsan" indicates that perfection is a decreed by Allah, and that all the creation are to fulfill it as an obligatory feature in every deed or to do their best to reach that rank.