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. LewisA tyrannous and gluttonous demand for affection can be a horrible thing. But in ordinary life no one calls a child selfish because it turns for comfort to its mother; nor an adult who turns to his fellow "for company." Those, whether children or adults, who do so least are not usually the most selfless.
C. S. LewisThe demand of the loveless and the self-imprisoned that they should be allowed to blackmail the universe: that till they consent to be happy (on their own terms) no one else shall taste joy: that theirs should be the final power; that Hell should be able to veto Heaven.
C. S. LewisThey have chosen cunning instead of belief. Their prison is only in their minds, yet they are in that prison; and so afraid of being taken in that they cannot be taken out.
C. S. LewisThe promise, made when I am in love and because I am in love, to be true to the beloved as long as I live, commits me to being true even if I cease to be in love. A promise must be about things that I can do, about actions: no one can promise to go on feeling in a certain way. He might as well promise to never have a headache or always to feel hungry.
C. S. Lewis