Ecumenism

Ecumenism is the effort to express or restore visible unity among Christian churches and denominations left divided from one another. The word comes from the Greek oikoumene, “the inhabited world,” and first named the early ecumenical councils that the whole church recognized as authoritative. Its modern sense, an organized movement toward cooperation or institutional reunion among separated churches, dates from the twentieth century. In a broader, non-theological sense the word is sometimes extended to movements seeking cooperation among the world’s religions generally, rather than among Christian bodies specifically.

Confessional Witness

None of the Reformed confessions uses the word “ecumenism”; the organized movement it names is a twentieth-century development the seventeenth century could not have anticipated. The confessional tradition does, however, address how far churches that remain visibly distinct may still act together. The 1689 Second London Baptist Confession allows particular congregations to send messengers to confer with one another “in cases of difficulties or differences,” while denying any resulting assembly “jurisdiction over the churches themselves, or any of them, in point of power.”¹ Cooperation among churches is contemplated, then, as consultation between still-distinct, self-governing congregations rather than as an authority standing over any of them, the same congregational polity the confession sets out in its chapter on the church.

Biblical Basis

On the night before his death, Christ prays for those who would believe through the apostles’ word, “that they may all be one, just as you, Father, are in me, and I in you, that they also may be in us, so that the world may believe that you have sent me” (John 17:21), and again “that they may become perfectly one” (John 17:23). The prayer for unity follows directly from an earlier petition in the same chapter, “sanctify them in the truth; your word is truth” (John 17:17), tying the unity Christ asks for to a shared truth rather than to agreement for its own sake.

Paul grounds the same unity in what believers already hold in common:

There is one body and one Spirit, just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of all, who is over all and through all and in all. (Eph. 4:4-6)

Van Mastricht draws out the force of Paul’s list: the apostle “heaps up various types of unity as so many motivating arguments” for “ecclesiastical unity,” moving from the church’s one Spirit and one hope to its one Lord, one faith, and one baptism, so that “induced by reasons of this sort, the primitive church… was united in one accord” (Acts 2:1, 44-46).² The same apostle rebukes the opposite tendency directly when he finds the Corinthian church splitting into factions named after human leaders: “each one of you says, ‘I follow Paul,’ or ‘I follow Apollos,’ or ‘I follow Cephas,’ or ‘I follow Christ.’ Is Christ divided?” (1 Cor. 1:12-13).

Historical Development

The early church distinguished two ways the body of Christ could be broken. Herman Bavinck states the distinction the fathers worked out: “the terms ‘heresy’ and ‘schism.’ The former breaks the unity of the church on matters of doctrine, the latter in fellowship of communion.”³ Both were counted serious sins, but the distinction mattered: a church could fracture into separate communions without any side having abandoned the faith once delivered, and it could hold together institutionally while parts of it taught something other than the apostles had taught.

By the medieval period that catholicity doctrine had hardened into an institutional claim: Rome located the church’s unity in a single hierarchy under the pope. The Reformation relocated it instead. Rather than in “the hierarchy and the papacy,” Bavinck writes, the church’s unity is found “in the spiritual unity of the church with its head… and further, with the unity of faith, hope, and love, and of baptism” (Eph. 4:3-5). That spiritual unity, he adds, “is not simply invisible, it comes to expression in that which all Christians have in common in spite of their divisions.”⁴ The Reformed tradition drew a further distinction to work out what genuinely divided Christians still hold in common: between fundamental and non-fundamental articles of the faith, a distinction meant to foster neither schism over trivial disagreements nor “indifferentism and syncretism” about the truth itself.⁵

Writing in 1932, Loraine Boettner named an “ecumenical movement” already well underway and traced it to a specific cause: declining doctrinal instruction in the churches. Neglect of “these distinctive doctrines,” he wrote, “led directly into the ecumenical movement in which attempts are being made to unite churches of very different types with only a minimum of doctrine.”⁶

Opposing Views

Roman Catholicism locates the church’s unity in a single visible hierarchy under the papacy; on this model, ecumenism aims at the eventual reunion of separated Christian bodies with Rome.

The modern ecumenical movement, on Boettner’s account, pursues visible cooperation or merger among churches by minimizing the doctrinal commitments that divide them, treating institutional unity as achievable apart from a shared confession of the truth.⁶

The Reformed confessional position holds that the church’s unity is a spiritual reality first, one that already exists among genuinely believing Christians “in spite of their divisions” rather than one that must be manufactured by institutional merger.⁴ Real, if incomplete, unity is expressed wherever believers across visibly divided bodies actually hold to the same fundamental articles of the faith; it is not achieved by loosening the doctrine that distinguishes true churches from false ones.

Objections and Responses

Refusing formal reunion with other communions seems to defy Christ’s own prayer “that they may all be one” (John 17:21). The prayer for unity in John 17 immediately follows a prayer for sanctification “in the truth” (John 17:17), so the unity Christ asks for is unity in a shared truth, not agreement achieved independently of it. On the Reformed account, that spiritual unity already exists among genuine believers across their visible divisions and is expressed by cooperation, not created by it; formal institutional merger was never what the prayer requires.⁴

Treating doctrinal precision as a barrier to cooperation looks like the very schism the Reformed tradition itself condemns. Van Mastricht warns believers to “beware, more than a dog or serpent, all schisms in the church, as well as schismatic contentions and arguments,” citing Paul’s own warnings against “disputes about words” and “irreverent babble” (1 Tim. 6:3-5; 2 Tim. 2:14).² But that warning targets contentiousness over trivial or verbal disagreements, not fidelity to doctrine itself. Bavinck’s own distinction holds: schism breaks fellowship without a corresponding break in the faith, while heresy breaks the unity of the church’s doctrine.³ Contending for a fundamental article of the faith is not the schismatic quarrel either writer has in view.

Related Doctrines

References

The Second London Baptist Confession of Faith (1689), chap. 26, “Of the Church,” para. 14-15. ↩
Petrus van Mastricht, Theoretical-Practical Theology, vol. 2, Faith in the Triune God, ed. Joel R. Beeke, trans. Todd M. Rester (Grand Rapids: Reformation Heritage Books, 2019), chap. 8, “The Unity of God,” 217-18. ↩ ↩²
Herman Bavinck, Reformed Dogmatics: Abridged in One Volume, ed. John Bolt (Grand Rapids: Baker Academic, 2011), chap. 21, “The Church as a Spiritual Reality.” ↩ ↩²
Bavinck, Reformed Dogmatics, chap. 21, “The Church as a Spiritual Reality.” ↩ ↩² ↩³
Bavinck, Reformed Dogmatics, chap. 21, “The Church as a Spiritual Reality.” ↩
Loraine Boettner, The Reformed Doctrine of Predestination (Grand Rapids: Wm. B. Eerdmans Publishing Company, 1932), 253. ↩ ↩²