"No man is an island"

Unfortunately, our human nature is always going to want to run away and from speaking the truth to others, to disengage. We see this tendency starting with the Israelites not wanting to be the kingdom of priests to the Gentiles like God wanted them to be. Further down is Jesus, and just in case we did not get the message, he prays in John 17 over his disciples, and consequently us, that we would not be taken out of the world, but that God would protect us from the evil one. Separation is not the point of the Christian life. The bit of history of this separation phenomenon is most clearly seen in the fundamentalist insistence to "come out from them and be ye separate." To one extent or another, that verse is taken out of the context that it is meant to function. Following Christ IS to be holy (separate). Plus, holy in the context of Scripture is not necessarily pure or free from sin, but set apart for a specific purpose. To move from picking on the fundies, a Christian's life is not to see how many trinkets in this life he can get, nor is it to help yourself or someone else with low self-esteem, nor is it even to feed the hungry, clothe the poor, just for their sake alone. One can indeed do all that and still not be known of Jesus (Matthew 7:21-23) without faith in him. Our purpose as Christians is to bring God glory (1 Cor. 10:31). In the moment of regeneration, our allegiance changes from ourselves, to God.

We must engage. Rom. 10:14-17. If we do not engage them through the preaching and teaching of the Gospel, they'll never know about Jesus. This is why we get food for a family who has nothing. This is why we get a coat for a kid that does not have a good one or one at all. This is our motivation--that the Gospel would go forth, that the kingdom would come, that God would be glorified all the more in the changed lives of his people.