Lewis makes a number of excellent statements about pride, which I am including:
“According to Christian teachers, the essential vice, the utmost evil, is Pride. Unchastity, anger, greed, drunkenness, and all that, are mere fleabites in comparison: it was through Pride that the devil became the devil: Pride leads to every other vice: it is the complete anti-God state of mind. . . . Pride is competitive by its very nature: that is why it goes on and on. If I am a proud man, then, as long as there is one man in the whole world more powerful, or richer, or cleverer than I, he is my rival and my enemy.
“The Christians are right: 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. . . . For pride is spiritual cancer: it eats up the very possibility of love, or contentment, or even common sense.”
Pride blocks the Counsel of the Holy Spirit, even His entry into our human spirit and soul.