In Galatians 3:28, we find God’s present-day plan for the Church: “There is neither Jew nor Greek” — one version says Jew nor Gentile — “neither slave nor free, neither male nor female, for you are all one in Christ.” So, there is unity in God’s plan. From the beginning, it was a unity of blood. We are all one in Christ.
The church, if no other element in society, should be a demonstration of unity, and unity with diversity, and diversity in that unity. We are one as a demonstration of the plan of God. So, how does this oneness thing end up?