You can be good for the mere sake of goodness; you cannot be bad for the mere sake of badness. You can do a kind action when you are not feeling kind and when it gives you no pleasure, simply because kindness is right; but no one ever did a cruel action simply because cruelty is wrong - only because cruelty is pleasant or useful to him, In other words, badness cannot succeed even in being bad in the same way in which goodness is good. Goodness is, so to speak, itself: badness is only spoiled goodness. And there must be something good first before it can be spoiled.
C. S. LewisWhen you are not feeling particularly friendly but know you ought to be, the best thing you can do, very often, is to put on a friendly manner and behave as if you were a nicer person than you actually are. And in a few minutes, as we have all noticed, you will be really feeling friendlier than you were.
C. S. LewisWe have to be continually reminded of what we believe. Neither this belief nor any other will automatically remain alive in the mind. It must be fed.
C. S. LewisThough no one would want to be sold as a slave, it is perhaps even more galling to be a sort of utility slave whom no one will buy.
C. S. LewisReally great moral teachers never do introduce new moralities: it is quacks and cranks who do that.... The real job of every moral teacher is to keep on bringing us back, time after time, to the old simple principles which we are all so anxious not to see; like bringing a horse back and back to the fence it has refused to jump or bringing a child back and back to the bit in its lesson that it wants to shirk.
C. S. Lewis