It is Pride which has been the chief cause of misery in every nation and every family since the world began. Other vices may sometimes bring people together: you may find good fellowship and jokes and friendliness among drunken people or unchaste people. But Pride always means enmity—it is enmity. And not only enmity between man and man, but enmity to God.
 
In God you come up against something which is in every respect immeasurably superior to yourself. Unless you know God as that—and, therefore, know yourself as nothing in comparison— you do not know God at all. As long as you are proud you cannot know God. A proud man is always looking down on things and people: and, of course, as long as you are looking down, you cannot see something that is above you.

That raises a terrible question. How is it that people who are quite obviously eaten up with Pride can say they believe in God and appear to themselves very religious? I am afraid it means they are worshiping an imaginary God. They theoretically admit themselves to be nothing in the presence of this phantom God, but are really all the time imagining how He approves of them and thinks them far better than ordinary people: that is, they pay a pennyworth of imaginary humility to Him and get out of it a pound’s worth of Pride towards their fellow-men. I suppose it was of those people Christ was thinking when He said that some would preach about Him and cast out devils in His name, only to be told at the end of the world that He had never known them. And any of us may at any moment be in this death-trap. Luckily, we have a test. Whenever we find that our religious life is making us feel that we are good—above all, that we are better than someone else—I think we may be sure that we are being acted on, not by God, but by the devil. The real test of being in the presence of God is that you either forget about yourself altogether or see yourself as a small, dirty object. It is better to forget about yourself altogether.
- C.S. Lewis

“Pride gets no pleasure out of having something, only out of having more of it than the next man. We say people are proud of being rich, or clever, or good-looking but they are not. They are proud of being richer, or cleverer, or better-looking than others.” 
- C.S. Lewis

 “For pride is spiritual cancer: it eats up the very possibility of love, or contentment, or even common sense.”
- C.S. Lewis

“The real black diabolical Pride comes when you look down on others so much that you do not care what they think of you. Of course, it is very right, and often our duty, not to care what people think of us, if we do so for the right reason; namely, because we care so incomparably more what God thinks. But the Proud man has a different reason for not caring. He says ‘Why should I care for the applause of that rabble as if their opinion were worth anything?’”
- C.S. Lewis