Some theologians believe that some of the early Christian martyrs - Peter and Paul included - were killed because of jealous strife in the church at Rome. They claim that rivalry was so bitter that some believers turned in the names of their Christian opponents, naming them as traitors to Rome. If this is true, envy among Christians helped feed saints to the lions in the Colosseum and light fires under Christians who burned in Nero's gardens. (Romans: Righteousness from Heaven, R. Kent Hughes) There is no room in the church of Jesus Christ for prejudice, racial superiority or ethnocentricity. The outbreak of tribal violence, even among Christians in the last Kenyan election cycle is a sober reminder of Paul's conclusion to his treatise on Justification by faith in the Book of Romans.
The unity of genuine believers is of great concern to Jesus Christ. In his final prayer before going to the cross he plead for his disciples to experience this unity. (Jn 17:11,20-23)
We are to receive one another as brothers in Christ because we share a common gospel, we were washed by the same blood of Christ, we have been justified through faith in Jesus Christ. We speak the same message of glory to God with our brothers and sisters around the world.
We are to accept one another despite our cultural differences and heritages. The basis for this acceptance of one another is not that we share a tribal identity, or similar cultural heritage, or similar understandings of complex issues. It is not based on the kinds of food we eat, or things we drink. It is not based on culturally important issues such as important days or customs and celebrations. The foundation for this unity is the gospel of Jesus Christ. The motivation for pursuing this unity is the sacrifice of Jesus Christ and the basis for this unity is the Word of God! (Ro 14-15)
Service then extends far beyond merely doing things for each other. Serving descends to the very core of who we perceive ourselves to be in relation to others within the body of Christ.