This unity of the church extends not only after The Cross, but also before Christ with the faithful in the Old Testament. In worship, we come to “Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, 23 and to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous made perfect” (Heb. 12:22-23). Anyone and everyone whose destiny is heaven has been enrolled and predestined to be there from all eternity. Therefore, they belong to the “assembly of the firstborn” with whom we worship God and are one.
As discussed in a previous chapter, the believers under the Old Testament were part of the same covenant which we now enjoy. Therefore, they belong to us and we to them because we have the same God, Savior, and Mediator (cf. Heb. 11:39-40). See chapter 8:6. Another point which points to our unity with believers under the Old Testament is the fact that all of us have the same father. Here, I’m specifically focusing on unity with Israelite believers. Paul’s argument for justification by faith throughout history may also be extended to include our unity with those who are justified in the same way we are (see Rom. 4 and chapter 11 of the Confession). Only those who have faith are truly the children of Abraham (Gal. 3:7, 28-29). In 1 Corinthians 10:1, the apostle Paul speaks of the wilderness generation as “our fathers [who] were all under the cloud, and all passed through the sea”. This unity extends itself in the unity of Jew and Gentile under the inaugurated New Covenant. In Ephesians 2, the apostle speaks of this unity in which God has torn down the dividing wall which stood between Jew and Gentile (Eph. 2:14). By breaking that wall of division, God has created peace between those who stood on both sides of the wall. He has done this by making one new man from the two.
Scripture not only speaks of unity as a fact, but also as an imperative and something to strive for. In Ephesians 4, God equips us until “we all attain to the unity of the faith and of the knowledge of the Son of God” (Eph. 4:13). The calls for unity in the New Testament are numerous. In Philippians 2:2, the apostle says, “complete my joy by being of the same mind, having the same love, being in full accord and of one mind.” The apostle Peter calls all of us to “have unity of mind, sympathy, brotherly love, a tender heart, and a humble mind” (1 Pet. 3:8).
Therefore, we see that the unity of the church is both a fact and something which we should strive for.
Universality of the Church
The catholicity of the church is the attribute which points to the fact that there is but one church of Christ. The unity of the church likewise touches on this point. But the attribute of catholicity shows that the church of Christ is everywhere in...