Romans 12:2 — Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. The you will be able to test and approve what God’s will is — His good, pleasing and perfect will.
The fact is that being a Christian isn’t very cool. It includes things like not believing in evolution, believing in what many people consider to be a “magical fairy god”, and disagreeing with many popular ideas, and trends. The trouble is that as humans we want to be “cool”, and liked by our peers. Because of this we are quiet about our God, and His amazing love. We don’t voice our opinions about issues that maybe we should, and sometimes we get caught up in things we shouldn’t be caught up in.
We are called to “not conform” “to the pattern of this world.” When our friends are doing things that aren’t Godly we are called to not participate. If your best friend is talking about the cool pornography he found the best thing to do might be to leave the room. As Ephesians 5:11 puts it “have nothing to do with the fruitless deeds of darkness.” We are told that we should instead “find out what pleases the Lord.”
That doesn’t mean that we can’t hang out with those people (maybe we shouldn’t) after all Jesus hung out with tax collectors, and prostitutes. The thing we should be doing is keeping our image pure. We shouldn’t be joining in and talking about what ever worldly things they are talking about. We should instead think, and talk about the things that glorify God.
Phillipians 4:8 — Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable, — if anything is excellent or praiseworthy — think about such things.