Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things.  What you have learned and received and heard and seen in me—practice these things, and the God of peace will be with you. (Philippians 4:8-9 ESV)
This passage is often misread to encourage believers to escape from the world, to retreat into a ghetto of their own making. Rather than engage the culture, they are told that they should surround themselves with only “Christian” influences. Escape the world and live within the hedges of the church community.
That sort of teaching contradicts too much Scripture to be a correct reading of this passage. Believers here are called to be a thinking people, to evaluate and engage world culture, not run from it. To know what is true, honorable, just and so on, the believer has Scripture and the Spirit. You don’t get such things from some “Christian” subculture. In fact, that subculture needs to be evaluated and judged just as much as the other, “secular” ones.
As we engage the world around us, we look for hints of the good qualities that point to or reflect the Gospel. Where we find them we can help people to understand that most important of stories and maybe change lives. If they are not there we can bring that void to the attention of the people around us.