Interesting verse to go with this one. Not sure if I would have guessed that one.
Separated but still within it, that is how we should be with the world. In it but not of it.
Yes in many ways you should keep separated from the world. We don't always have the same goals, priorities, enemies, purposes, knowledge or wisdom of the world. Our beliefs are different. What we live by is different. What we believe in is different. We are not going in the same direction as the world quite often. So yeah in many ways we are separate from the world. Some degree of mental and emotional separation is required to stay on the path and stay focused on Jesus so we don't fall away into the world's ways.
However, we are still physically in this world. Unless its your day to go home you're still here. We still have a mission to this world, to disciple to it, spread the gospel, and save as many people as we can until God calls us home. We still have a duty to it as Christians. You can't fulfill this duty if you are literally separated from it as much as possible and not interacting with it in any way.
You have a job to do here, but this is not your home. To those that have sold their souls for this temporary world leave them be, they have received their reward in full. There are still those out there who can still be saved though, and we must go to them and bring them the hope we have been given through Jesus. Remain as a visitor here, passing through but not a part of it.
With hammer in hand, I began to pull out every nail. Every board I placed beside me on the damp ground. After many years of pouring everything I could into avoiding that way, I found myself walking there once again.