You may have noticed that modern people are nearly always thinking about the first thing [fair play and harmony between individuals] and forgetting the other two [internal correction and the purpose of human life]. When people say in the newspapers that we are striving for Christian moral standards, they usually mean that we are striving for kindness and fair play between nations, and classes, and individuals; that is, they are thinking only of the first thing. When a man says about something he wants to do, “It can’t be wrong because it doesn’t do anyone else any harm,” he is thinking only of the first thing. He is thinking it does not matter what the ship is like inside provided that he does not run into the next ship. And it is quite natural, when we start thinking about morality, to begin with the first thing, with social relations. For one thing, the results of bad morals in that sphere are so obvious and press on us every day: war and poverty and graft and lies and shoddy work. And also, as long as you stick to the first thing, there is very little disagreement about morality. Almost all people at all times have agreed (in theory) that human beings ought to be honest and kind and helpful to one another. But though it is natural to begin with all that, if our thinking about morality stops there, we might just as well not have thought at all. Unless we go on to the second thing—the tidying up inside each human being—we are only deceiving ourselves.
Mere Christianity, 71f.