Epictetus, Enchiridion 11

Your present opinion founded on understanding, your present conduct directed to social good, your present disposition contented with everything that happens — that is enough.

He who acts unjustly acts impiously. For since the universal nature has made rational animals for the sake of one another, he who acts contrary to nature commits impiety against the highest divinity.

This thou must always bear in mind, what is the nature of the whole, and what is my nature, and how this is related to that, and what kind of a part it is of what kind of a whole.