True catholicity: unity in the truth
Some claim that the church’s catholicity refers simply to believers scattered across the world, regardless of whether they belong to true or false churches. They speak of an “invisible catholic church” composed of all Christians everywhere.
But Scripture does not speak this way, and neither do our confessions. The early church already understood this. The Apostles’ Creed confesses the “holy catholic church” as the communion of saints. (Rev. de Marie [i] notes in his third article how the two phrases are separated merely by a comma.) The Heidelberg Catechism explains that in this communion believers share in Christ’s gifts and use their gifts for the benefit of one another. Catholicity is therefore concrete, visible, and expressed in real fellowship.
The Belgic Confession (Articles 27–29) expands this further. It teaches that the true church is a visible assembly of believers recognized by its faithful adherence to Scripture—shown in pure doctrine, proper administration of the sacraments, and the exercise of discipline. By maintaining these marks, says Rev. S. de Marie, the church acknowledges Christ as its only Head. And because Christ has only one body, the church must be united.
The call to join the true church
Hence Article 28 emphasizes that believers are commanded to join themselves to this true, catholic church. We do not join out of personal preference or convenience, but because:
- * Christ gathers His people there
- * Salvation is proclaimed there
- * Unity is preserved there
To refuse to join is to harm oneself spiritually and is to disobey the Lord’s command to join, says Rev. de Marie. Submitting to the church’s instruction and discipline is part of taking Christ’s yoke. It includes mutual service, edification, admonition, and discipline—all for the believer’s salvation.
Testing the church: the marks and catholicity
Article 29 adds the need for careful discernment. Many assemblies call themselves “church” but are not. Believers must continually test whether their church still bears the marks of the true church and whether it remains truly catholic—committed to truth and to unity with other true churches.
This includes striving for federative unity locally and forming sister-church relations abroad wherever possible. True churches in the same region or country should seek to become one federation.
Rev. de Marie stresses that catholicity is dynamic. Christ reforms churches that have strayed, but churches can also decline to be reformed or they can enter false associations. If they refuse repentance, separation may become necessary. This ongoing discernment is not merely historical advice—it is the biblical path Christ sets before believers, congregations, and federations: following Him in faith, submitting to Him as Head, and glorifying Him and the Father, as expressed in His High Priestly Prayer.
Distortions of catholicity
In his fourth and final article on Catholicity versus Pluriformity, [ii] Rev. de Marie points to some distortions of catholicity.
1. Sects and the false church: unity without truth
Some groups call themselves “church” and even form international networks, yet they do not bear the marks of the true church. Article 29 identifies these as sects or false churches. When such bodies cooperate, the result is false ecumenism—unity built on error.
For example, the Roman Catholic Church is global and unified, but not catholic according to Scripture. Its unity rests on the Pope rather than Christ, says Rev. de Marie, and its doctrine contradicts God’s Word in key areas. It has organizational unity, but not unity in the truth.
2. Reformed pluriformity: cooperation without obedience
Since the Secession of 1834, various Reformed federations have shared the same confession yet refused to pursue full unity. Some cooperate in activities such as pulpit exchanges and conferences while avoiding the substantive work needed for true ecclesiastical unity.
This contradicts Christ’s command for perfect unity. The highly respected Dutch reformed theologian, Prof. S. Greijdanus, was asked at a 1948 gathering whether cooperation in broadly Christian organisations was possible. His response: pursuing such cooperation without addressing the question of church unity neglects obedience to Christ.
A deeper problem arises when churches form domestic or foreign sister-church relations without uniting in their own region. The Canadian Reformed Churches illustrate this, says Rev. de Marie. He notes that their “ecclesiastical fellowship” allows pulpit and table fellowship without full unity. This acceptance of pluriformity leads to tolerating practices contrary to Reformed doctrine, such as open communion and lack of confessional binding.
3. Presbyterian pluriformity: denominationalism
Some Presbyterian churches, such as the OPC, base unity on their interpretation of the Westminster Standards, says Rev. de Marie. They sharply distinguish between the “visible” and “invisible” church and accept churches of varying purity—including Baptist churches—as true churches of Christ.
Binding to the confession is not required, he adds, and open communion is practised. This produces impure unity: fellowship with non‑Reformed believers and cooperation without unification. In the process, the truth itself is compromised.
4. Schismatic churches: truth without unity
Other churches maintain pure doctrine but refuse to seek unity with fellow true churches. They remain isolated and ignore Christ’s call to practice fellowship.
Historically, says Rev. de Marie, the Christelijke Gereformeerde Kerken (CGK) in the Netherlands were seen as schismatic because they rejected unity with the Reformed Churches (GK). The Reformed Churches (Liberated) repeatedly sought unity from 1944 to 1990 but were refused. Yet if such churches later seek contact with true churches in their region, they can still become part of the worldwide catholic church.
Our task
A church that faithfully maintains the truth and actively seeks unity in that truth is truly catholic—even if small or despised, says Rev. de Marie. Isolation is not an option; churches must continually call others to reformation, and when mutual recognition exists, unification becomes a duty.
May the Lord bless such efforts toward unity in the truth.
Conclusion
To belong to the one holy catholic apostolic church, a church must bear the marks of the true church (Article 29 BC) and obey Christ’s command for perfect unity.
Drawing some further conclusions from what Rev. de Marie has said, this means:
- True churches in the same region or country must unite in one federation.
- Abroad, unity takes the form of sister‑church relations with shared pulpit and table fellowship, guarded by mutual oversight in doctrine, government, discipline, and worship.
- Churches must continually test themselves and their relationships to ensure both truth and unity are preserved.
Ecclesia reformata semper reformanda—the church must always be reforming according to God’s Word, holding the truth in love, and following Christ as one flock under one Head.
[i] CATHOLICITY VERSUS PLURIFORMITY 3 – Bouwen en Bewaren
[ii] CATHOLICITY VERSUS PLURIFORMITY 4 – Bouwen en Bewaren