But it's not as easy as that. Christians must live in their culture, but they dare not take their lead from it. You may make your living today in the world of business, or go to school in the world of education, or enjoy entertainment in the world of music or media. But the world-system in which we live is enemy territory. It is not neutral.
Worldliness is anything that makes sin look attractive and righteousness look silly.
We are worldly whenever we live and love and choose on the same basis as people who don't love God. A Christian striving for power in a church or exploding at his wife at home can be as worldly as a person guzzling drinks at a bar. He wants us to be in the world, but not to be of it. Christians must live in the world but not let the world live in them.