Principles of the Unity of the Church The church is the covenant people of God—the body of people to whom God has made the promise to be their God and they to be his people and he to dwell with them. The church is the covenant people of God in all ages and among all nations. All those who believe the promise of God and their children and have had the promise sealed to them in baptism are to be recognized and treated as God's people, as members of the organized church. The church belongs to her covenant head Jesus Christ and "there is no other head of the church but the Lord Jesus Christ.
The work of the church, in fellowship with and in obedience to Christ, is divine worship, mutual edification, and gospel witness under the teaching and rule of elders. The Lord governs his church also through the application of his Word to the people by the Spirit as the Word is expounded and applied by the officers of the church (Eph. 4:11-16). The church finds its unifying principle in the covenant promise "my dwelling place will be with them; I will be their God, and they will be my people" (Ezek. 37:27, Lev. 26:12). This finds fulfillment in Jesus as Emmanuel ("God with us," Matt. 1:23, Jn. 1:14), who came as the mediator of the covenant of grace to redeem and purchase this people for his dwelling by his blood. The ultimate consummation of the promise is the new Jerusalem, the Bride of Christ (Rev. 21:3).
The church must recognize, appreciate, and confess this fundamental unity of the covenant people of God, the body of Christ; which is a God-given creation and not a human achievement. The church, the visible organization, is described in the Bible as one church. God has given only one covenant of love (Deut. 7:6-12) and has only one people of the covenant. In the New Testament this teaching of the unity of the people of God is sustained (see Eph. 2:11-22 and 4:1-16). Yet the situation is different. No longer are the people of God circumscribed by ethnic, political, or geographical boundaries.
The gospel proclaimed by the apostles as the foundation of the church resulted in establishing churches as covenant communities in various locations, churches which were ruled by elders. These churches and these elders were not independent, but were one body united by Christ their head, by the abiding presence of the Holy Spirit, and by the covenant promise of God. The elders at Antioch and Jerusalem resolve a problem, under God, and their decision is binding on the churches (Acts 15, 16:4). The unity of the church is attained unto by growing in spiritual maturity (Eph. 4:13). Unity and maturity are the result of mutual, loving admonition and joint submission to Scripture. Such maturity is manifested by speaking and acting the truth in love (Eph. 4:15). Each member is essential to the body, and the growth of the body depends on the active participation of each part (Eph. 4:13, 16). The work of the officers of the church is to prepare the members for, and assist them in this work (Eph. 4:11-12).In ecclesiastical union two denominations join in submitting to one common form of government.
Since ecclesiastical jurisdiction includes the maintenance of spiritual discipline, unity in polity requires agreement in the standards of faith and worship which such discipline maintains. Hence unification in polity, when properly sought and achieved, involves also unity in faith, discipline, and worship.Though the diversity which manifests itself in differentiating historical development might appear to make ecclesiastical union inadvisable or even perilous in certain cases, yet the biblical evidence in support of union is so plain that any argument to the contrary, however plausible, must be false.In Christ there is now no longer Jew or Gentile, barbarian, Scythian, bond nor free (cf. Gal 3:28; Col. 3:11).
The New Testament does not suppose that the differences natural to individuals nor those arising from ethnic identity, cultural background, and historical circumstance are to be obliterated by the gospel. But it does mean that the unity of Christ transcends all diversity arising from language, race, culture, history. What is more, this unity embraces and utilizes all the diversity that is proper and this is created by God's providence.
If we should maintain that the diversity is in any way incompatible with the unity of which the church is the expression, then we should be denying THAT unity which the ethnic universalism of the gospel implies. Implicit in the universalism of the gospel is the same kind of universalism in that which the gospel designs, the building up of Christ's church.The church of the apostolic days embraces all nations, and kindreds, and peoples, and tongues. There is no evidence in the New Testament for the diversification of distinct denominations and anything tending to such diversification was condemned (cf. 1 Cor. 1:10-13). The emphasis falls upon the oneness of faith (cf. Eph. 4:5) and the oneness of the fellowship of the saints (cf. Eph. 4:2-4; 11-16; Phil. 2:2, 3; Christ is the head of the church.