17And he came and preached peace to you who were far off and peace to those who were near. 18For through him we both have access in one Spirit to the Father. 19So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, 20built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, 21in whom the whole structure, being joined together, grows into a holy temple in the Lord. 22In him you also are being built together into a dwelling place for God by the Spirit.
Jesus came and preached peace to those who were near (the Pharisees, those who understood and obeyed the law, the Jew who earnestly practiced their faith, those who cited the fact that we should love God with our heart, mind and soul) and those who were far (the tax-collectors, prostitutes, gentiles). I believe that peace is the gospel message of peace and reconciliation to God through faith. And a large part of that message was the loving of those God created (as illustrated in the parable of the Good Samaritan, for one). That faith includes giving of yourself not only for God, but for your neighbor, whom you are told to love as you love yourself.
So we are no longer strangers, aliens, enemies even, but we are connected together through God himself. We are part of a holy temple. Imagine building a building where the components of that building to not work together. What if the mortar, which is different from the bricks, refused to bind together with the bricks? What if the shingles of a buildng refused to let themselves be seen with the tar paper that is laid beneath them? So we must embrace our differences because they are needed in order for the building to perform its function. I am not saying that we accept destructive forces that would tear the building down. You don't observe a mold and continue to let it grow in the building, that would destroy the building.
Jesus came to reconcile man to God. In the process, he reconciled men with one another, because how can the body be reconciled to God and yet at war with its members?