Have I done anything kind? Then I have gained from it. Keep this thought always in your mind. Never stop thinking about it. What is your job in life? To be good. And how can you do this well? Only by learning certain principles — some about how the universe works, and some about what makes humans tick.
Have I done anything charitably? then am I benefited by it. See that this upon all occasions may present itself unto thy mind, and never cease to think of it. What is thy profession? to be good. And how should this be well brought to pass, but by certain theorems and doctrines; some Concerning the nature of the universe, and some Concerning the proper and particular constitution of man?