The church is called to reach out into the world. Practically what this means is the church must seek and be willing to accept all who call upon God for the forgiveness of sins.
It is not an easy calling. God has a tendency to call all sorts of people to himself. He often calls people who we would not expect and some of whom may not be at the best places in their lives.
It is often difficult for churches who are over zealous for purity to accept such people. It is a common issue we find throughout scripture where the teachings of God on righteousness are misunderstood where the "otherness" of the believer begins to infringe upon the ability to relate with unbelievers or those struggling in their lives.
You see that our "righteousness" must not be more extreme than the righteousness of Jesus. We often see the error of the Pharisees, but we do not see that we might at times exemplify some of the errors. It is easy to wish to pull back from interacting with certain people with a bit of a rougher edge.
Really the error of the Pharisees in wanting to separate from the world continues in the church and is very prevalent in certain segments of the church today. It is often in less extreme forms but often the church pulls back and is far more cautious in relation the the world than is necessary.
There are of course segments of the church which go the opposite direct and lose a sense of the otherness a Christian should have in their attempt to evangelize. Sometimes they even lose a sense of gospel as the distinction between church and world becomes more and more thin.
It is always a balance. We must seek righteousness, but not at the expense of our ability to reach out into the world. But we must always maintain a separateness.
One Christian thinker said that as long as there were those who criticized him as being both a legalist and a law breaker than he had balance in theology. There is a lot of truth to this. You see often in theology we need to find a balance between two extremes. It is not easy, but complete loss of balance is the most common theological downfall.