Read Ephesians 2:11-18
God has reconciled both Jews and Gentiles to Himself. Therefore, when the Jew and the Gentile receive Christ as Saviour, they can be at peace with each other because they are at peace with God.
Once God has become their Father, they can gladly call each other "brother." And it is only when individuals are in right relationship with God that they can be in complete harmony with each other.
This means that our deepest racial problems can never be completely solved until those involved come to know Christ as their Saviour and yield their lives to His control. Only the Christian has the basis for truly solving the problems that people face.
Jesus Christ reconciled both Jew and Gentile to God "in one body by the cross" (Eph. 2:16). The moment they were united to God through faith in Christ, they were united to one another. They became members of the same body--the Body of Christ.
So all the redeemed of this age are spiritually united on earth as the Body of Christ; and the risen, ascended Christ is in heaven as the Head of the Body.
As the Head, He gives life and direction to the members of the Body. Each believer is to no longer consider what he was in the natural realm but is to consider what he is in Christ.
Regardless of one's nationality, color or denominational preference, he becomes one in Christ with every other believer when he receives Christ.
"For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free" (1 Cor. 12:13).