Ephesians 2:11-22 describes a similar kind of situation. But instead of two physical cities separated by a physical wall, we have two groups of people separated by the Old Testament Law. One group of people were the Jews, the chosen people who had God's Law, the revelation of the prophets and ancestry from Abraham and the promise given to him. Because God had chosen them, the Jews looked down on everyone else, calling them Gentiles; people outside of the promise, without the Law and uncircumcised.
On the other side of the wall were the Gentiles. The Gentiles might be Roman, Greek, Egyptian, or any of a myriad of other nationalities. They had a wide variety of social, economic or educational levels. They included probably 99% of the worlds population. But what they had in common was being outside of the covenant relationship with God, not living under the Law, and without knowledge of God.
And separating the two groups is the Law, the commands given through Moses to the Hebrew people at Mt Sinai, at the beginning of their life together as a nation. This law effectively separated them from all other peoples, making them unique and establishing a covenant relationship with the God of creation. And built into the law is the expectation that they would separate themselves from all of the peoples around them, holding themselves apart and holy to God.
Now while it was marginally possible for a Gentile to cross over that wall and enter into the covenant relationship with God, it was not easy. And as a consequence not many did it. Many more would climb to the top of the wall and get close, but would not be willing to go all the way. And the Jews, for their part, seemed not very interested in helping Gentiles to cross their barrier.
But then, about 2000 years ago, Jesus was born, lived for about 33 years and then was crucified on a Roman cross, an apparent victim to his own peoples dislike for his attempting to change the statue quo. But Paul tells us here that this event was really much more than it appeared. According to Paul, the blood of Jesus, shed on the cross, brought reconciliation between the two camps, and distroyed the wall of hostility that seperated the two, producing a single humanity where once there had been two.
What was this wall of hostility that is destroyed at Jesus death? Paul indicates here that it is the law, along with its commandments and regulations. But how does this jive with Matthew 5:17 where Jesus says he has not come to abolish the law but to fulfill it? I think this question is best answered by Paul in Galatians 3:23-25 where he claims that the purpose of the law is to bring us to Christ, and once that has been accomplished, or fulfilled, then we are through with the law. Once I have come to Christ I am no longer under the law, but am under grace (Romans 6:14).
In Christ it makes no difference whether we are Jew or Gentile. We are all one body in him because of grace. It is by faith in what Jesus did that we come into relationship with God now; not by adherence to the commands and regulations of the law. Because observance of the law as a means to righteousness has been replaced by God's grace, we are all equally able to stand before God, not because of what I have done, but because of what he did.
And now we all can be built up into one house, or body, that God is able to inhabit and be glorified in. Let there be nothing in our lives or attitudes that would divide us as believers or cause us to think more highly of ourselves than of any other believer; or any other person. And rather than erecting more walls to make it difficult for people to come to God, lets reach out to the world around us and introduce them to the Savior.