Epictetus

“ Do you suppose I am speaking of some external God, made of silver or gold? It is within yourself that you bear Him, and do not perceive that you are defiling Him with impure thoughts and filthy actions. ”

“ But when God Himself is present within you, seeing and hearing everything, are you not ashamed to be thinking and doing such things as these, O insensible of your own nature, and object of God's wrath!
15Again, when we send a young man forth from the school to sundry activities, why are we afraid that he will do something amiss—eat amiss, have intercourse with women amiss, be abased if dressed in rags or conceited if he has on fine clothes? This fellow does not know the God within him, this fellow does not know the companion with whom he is setting forth. ”

“ Plants are incapable of dealing even with external impressions; for that reason you do not speak of the "good" in referring to them. The good requires, therefore, the faculty of using external impressions. ”

“ I will show you the sinews of a philosopher. What do you mean by sinews? A desire that fails not of achievement, an aversion proof against encountering what it would avoid, an appropriate choice, a thoughtful purpose, a well-considered assent. ”