Screwtape shows Wormwood how to transform a minor trespass into a major sin:
Success here depends on confusing him. If you try to make him explicitly and professedly proud of being a Christian, you will probably fail; the Enemy’s warnings are too well known. If, on the other hand, you let the idea of ‘we Christians’ drop out altogether and merely make him complacent about ‘his set’, you will produce not true spiritual pride but mere social vanity which, by comparison, is a trumpery, puny little sin. What you want is to keep a sly self-congratulation mixing with all his thoughts and never allow him to raise the question ‘What, precisely, am I congratulating myself about?’ The idea of belonging to an inner ring, of being in a secret, is very sweet to him. Play on that nerve. Teach him, using the influence of this girl when she is silliest, to adopt an air of amusement at the things the unbelievers say. Some theories which he may meet in modern Christian circles may here prove helpful; theories, I mean, that place the hope of society in some inner ring of ‘clerks’, some trained minority of theocrats. It is no affair of yours whether those theories are true or false; the great thing is to make Christianity a mystery religion in which he feels himself one of the initiates.
From The Screwtape Letters
Compiled in A Year with C.S. Lewis