Through the administration of the mystery, the manifold wisdom of God is made know through the church to rulers and authorities in the heavenly places (Ephesians 3:9-10).
The “mystery” is something hidden in God for ages past and now revealed in Christ. In Ephesians, the mystery is the union of Jews and Gentiles in the one body of Jesus, that Gentiles are “fellow heirs and fellow members of the body, and fellow partakers of the promise” (3:4-6).
How is this a proclamation to the principalities and powers, rulers and authorities in heavenly places?
Principalities and powers rule by division and domination, by dividing the world into masters and slaves and ensuring that masters dominate, by turning the fruitful created difference of male and female into a structure of oppression, by protecting the wealth of the wealthy and justifying indifference to the poor, by turning healthy diversity of languages and cultures into mutual hatred.
The union of Jews and Gentiles in the church is a proclamation that these fleshly markers of division have been transfigured by the resurrection of Jesus. Masters treat slaves as brothers and slaves act as freemen in Christ; man and woman are reconciled in one flesh by the Spirit; the wealthy open their hands in generosity, so that the poor can have enough to share; people of different nations are bound together by mutual exchanges of goods.
None of these realities is perfectly realized in the church. Christian masters are cruel, Christian husbands and wives abuse one another, rich Christians hoard wealth and poor Christians live in resentment and bitterness, national hatred divide the church.
Yet the mystery does become visible in the church. And even when it does not, the Word, Spirit, and Sacraments continually call the church to repentance, to more fully live in and exhibit the mystery.
In a word, the sheer existence of the church exposes the lies of the rulers and authorities, the lie that social order requires structures of division and domination. The fact that the church exists at all is a sign that fleshly patterns of life no longer reign. There’s another game in town, another civic order within the city of man.
The biblical word for all this is koinonia, “communion,” which captures both the bond that holds the members of the body together and the practices that both express and continually re-enliven this bond.
The church is one, the church exhibits the mystery of reunion of Jews and Gentiles, because her members have a common (koinon) share in the Spirit and in Christ. The union isn’t “merely social,” but Spiritual.
Christians are called into koinonia with the Lord Jesus (1 Corinthians 1:9). Paul ends 2 Corinthians commending the church to the koinonia of the Spirit (13:14). Having koinonia in the Spirit, Christians are to pursue unity of mind, purpose, and love (Philippians 2:1-2), as we share in a common mission (Philippians 1:5). Paul longs to know the koinonia with the sufferings of Christ (Philippians 3:10).
The Eucharist is a ritual expression of the koinonia of the church, also a means to realize that unity (1 Corinthians 10:16). Sharing bread together makes us one body in the Bread who comes from heaven.
For Paul, the practices of generosity are also an expression and re-enforcement of the church’s koinonia. Many of the New Testament’s uses of the term refer to sharing material goods to meet needs (Acts 2:42; Romans 15:26; 2 Corinthians 8:4; Hebrews 13:16).
Jews and Gentiles are united by the Spirit in Christ, but for Paul this union is realized by sharing of goods – the Jews sharing their Spiritual goods with Gentiles, and Gentiles responding with funds for famine relief in Jerusalem.
As Tim Gallant has pointed out, Romans 15:26 is particularly striking. Paul tells the Romans that the Macedonians made a koinonia for the poor saints in Jerusalem. This doesn’t merely mean that they made a contribution; it doesn’t mean that they threw money at a problem at a great distance. Rather, it means that their generous gifts overcame the geographic distance, joining Macedonian Gentiles and Jerusalem Jews in one fellowship of the Spirit. Gifts have a quasi-sacramental power to join the members of the church into one body.
Thus, every time the church celebrates Eucharist, or gathers donations to relief victims of a natural catastrophe on the other side of the world, or reconciles warring tribes, it is bringing the mystery to light, making known the wisdom of God to the rulers and authorities. Every time the church exhibits koinonia, she demonstrates that the rulers and authorities are powerless.