Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.
What is meant by "the world" or, as we commonly say, "wordliness?" I think a fair definition is that "this world" is the current, fallen, prevailing system of values and emphases which is in rebellion against God. It is a term which contrasts one system to the system of God's kingdom. It might also have an eschatological import -"this world" versus "the age to come."
Examples of Values:
1. Autonomy - American culture, especially, values "freedom." We value "tolerance" and personal autonomy. We don't like the idea of accountability. We want to be our own man/woman. It is, in many ways, the golden calf of our society. God says that what we ought to value is being a slave to Christ, who is Lord and King. This is what our faith mandates and tells us is infinitely more joyful and good than self-rule.
2. Self-esteem - Things like guilt are seen as distasteful or destructive. It is essential to see, it is imagined, that all societal and relational problems result from a fractured self-esteem. However, when is the last time you read a pop-psychology self-help manual on esteeming others? The Bible says we gain our "self value" in God, having Him as the basis for our identity, but even that "self value" is all about serving Him and serving others. There is a direct conflict between the value of self-esteem and the value of other-esteem.
Examples of Emphases:
1. Family - Family is good. However, it is of the world to place family where God belongs. I have heard it said even from people I grew up with that, "All that matters is family." Well, family is important, but no... not true. God takes the center. Family finds its rightful place only through that lens.
2. Fitness - Taking care of your body is good. It is a gift of God. We don't want to be destructive with God's gifts. However, television shows and commercials, for example, want us to fear "fat people hell" above all costs. What is promoted is building your life upon your fitness, your vitality, your looks, your youth, your waiste-line. Again, this is making a good thing an ultimate thing -an idol.
So, "the world" is basically a system of idolatry which takes God out of His rightful place in our lives. It is the prevailing system of thought, maybe even the big umbrella worldview of all the worldviews in opposition to the one God imposes through His Word and coming Kingdom.
What ought our response to be to "the world" or "worldliness?" That seems pretty clear from Scripture, but sometimes I think we may become imbalanced with it. We are to not be "friends" with it. We are to not be "conformed" to it. I take this to mean that we are not to be a) accepting of it and b) emulating it. We are called to a "narrow path." This is simply to say that we are to not engage in or approve of idolatry.
So far so good. What I think becomes problematic, though, is when two things happen. First, Christians assume it is as simple as "Christian" versus "non-Christian." We get suck on labels, external categories. As Mark Driscoll basically asked in his book "Radical Reformission," why exactly is Bible-man so much better than Spiderman? We must remember that "the world" is defined by values and emphases. If we do, we will realize that there is plenty of "worldliness" even in Christian circles. We tend to overlook these things, though, because they take place within the four-walls of the Church. An example might be gluttony at those yummy pot-lucks or self-righteousness in dealing with others, especially unbelievers. Self-righteousness seems to assume that we have a special standing that is our own, which others lack, and neglects that any standing, such as our justification, is purely a gift of grace.
Second, as a result of this, Christians may forget the major calling to be salt and light in the world, to love our neighbors, and to not be lights set under a basket. We withdraw from the "non-Christians," thinking that we are doing well in abstaining from worldliness. Don't get me wrong, there are aspects of the unbelieving culture around us that we certainly should avoid because they would tempt us and lead us to sin. I'm not going to try to minister to someone about Jesus while sitting in a strip club. However, at times I wonder if we gain the false impression that not conforming to the world (system) means withdrawing from the world (other people) and not caring about them. That isn't what Jesus did, from what I see.