Actus purus

In scholastic philosophy, actus purus ( literally "pure act") is the absolute perfection of God.

Created beings have potentiality that is not actuality, imperfections as well as perfection. Only God is simultaneously all that He can be, infinitely real and infinitely perfect: 'I am who I am' (Exodus 3:14). His attributes or His operations, are really identical with His essence, and His essence necessitates His existence. (Contrast this understanding with the Essence–Energies distinction in Eastern Christian, particularly Palamite, theology).