I now come to that part of Christian morals where they differ most sharply from all other morals. There is one vice of which no man in the world is free; which every one in the world loathes when he sees it in someone else; and of which hardly any people, except Christians, ever imagine that they are guilty themselves. I have heard people admit that they are bad-tempered, or that they cannot keep their heads about girls or drink, or even that they are cowards. I do not think I have ever heard anyone who was not a Christian accuse himself of this vice. And at the same time I have very seldom met anyone, who was not a Christian, who showed the slightest mercy to it in others. There is no fault which makes a man more unpopular, and no fault which we are more unconscious of in ourselves. And the more we have it ourselves, the more we dislike it in others.
The vice I am talking of is Pride or Self-Conceit: and the virtue opposite to it, in Christian morals, is called Humility.
The Vice of Pride according to Lewis – Part 1
C.S. Lewis, “The Great Sin,” Mere Christianity (1952; Harper Collins 2001) 121.