Many Christians and churches today practice to varying degrees what I call fortress mentality. These Christians almost never associate with anyone outside of their church. They only listen to Christian broadcasts and read only Christian books and media. It is almost as if they believe that if you are part of this world they will somehow be polluted by it and lose their faith. The only way they see to remain in Christ is to almost totally separate themselves for the rest of the world. Of course, this mentality is very counter to the actual words of Jesus.

Matt 28:19-20

Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
 

The Great Commission above is the bedrock of the Christian faith. But, it is very difficult to make disciples of all nations while we are hunkered down in our safe fortresses! We have to get out amongst them and get dirty to make Jesus’ words a reality. When Jesus said we are to be our brothers keeper he told us to be in the world but not of the world. Let’s all do what he says.