In many previous posts we have shown how certain paedobaptists (see links at end) have correctly understood that the distinction between the visible and invisible church is a matter of perspective: our fallible perspective vs God’s infallible perspective. As Bannerman noted, infant baptism is based upon the belief that professors and their children are members of the church in God’s eyes. He explains how infant baptism is rooted in a belief that the children of professors, as well as unregenerate professors, are members of the covenant in God’s eyes (see here for a collection of reformed resources on this point). But every time reformed theologians wrestle seriously with Roman Catholicism’s claims regarding the church, they resort to the correct conclusion that the visible/invisible distinction is a matter of perspective: only true believers are members of the church, though we mistakenly think that unbelievers are at times.
Baptists believed that the church is the body of Christ, those united to Christ in faith, the called elect, the members of the New Covenant. When paedobaptists object by pointing out that baptists don’t have regeneration goggles because unbelievers are baptized members of baptist churches, they fail to properly understand the distinction between the visible and invisible church. Yes, we baptize and admit to church membership based upon profession and that profession could be false. But membership in a local church is merely a human perspective of the church. The fact that we mistakenly consider a false professor to be a true believer does not mean the false professor is a member of the church – it just means we think they are.
Here is how Bavinck articulated that biblical understanding.
The word קָהָל (qāhāl), ἐκκλησια (ekklēsia), by virtue of its derivation from verbs that mean “to call together,” already denotes a gathering of people who come together for some purpose, especially a political or religious purpose, or, even if at a given moment they have not come together, are nevertheless mutually united for such a purpose. Under the Old Testament dispensation Israel was the people that had been called together and convened for God’s service. In the New Testament, the people of Israel have been replaced by the church of Christ, which is now the “holy nation, the chosen race, the royal priesthood” of God. The word “church” (kirk, kerk, kirche, chiesa), used to translate ἐκκλησια, does not express as clearly as the original this character of the church of Christ. It is probably derived from κυριακη (kyriakē; completed by οἰκια [oikia, house] being understood) or κυριακον (kyriakon; completed by οἰκον [oikon, house] being understood) and hence originally meant, not the congregation itself, but its place of assembly, the church building. Today we use the word in the sense of the building or of the worship service (“church starts at 10:00 a.m.”) or of the organized group of congregations (the Roman Catholic or the Anglican Church). In the word “church” the meaning of the New Testament word ἐκκλησια has been obscured. In certain periods the sense that “church” is the name for “the people of God” has almost totally eroded…Herman Bavinck, John Bolt, and John Vriend, Reformed Dogmatics: Holy Spirit, Church, and New Creation, vol. 4 (Grand Rapids, MI: Baker Academic, 2008), 296–313. This full section is available online.
Now there is no doubt that according to Scripture the characteristic essence of the church lies in the fact that it is the people of God. For the church is a realization of election, and the latter is election in Christ to calling, Justification, and glorification (Rom. 8:28), to being conformed to the image of God’s Son (8:29), to holiness and blessedness (Eph. 1:4ff.). The blessings granted to the church are primarily internal and spiritual in character and consist in calling and regeneration, in faith and Justification, in sanctification and glorification. They are the goods of the kingdom of heaven, benefits of the covenant of grace, promises for this life and, above all, for the life to come.
On these grounds, the church is the body of Christ (1 Cor. 12:27; Eph. 5:23; Col. 1:18), the bride of Christ (2 Cor. 11:2; Eph. 5:32; Rev. 19:7; 21:2), the sheepfold of Christ who gives his life for the sheep and is known by them (John 10), the building, the temple, the house of God (Matt. 16:18; Eph. 2:20; 1 Pet. 2:5), built up out of living stones (1 Pet. 2:5) on Christ as the cornerstone, and on the foundation of apostles and prophets (1 Cor. 3:17; 2 Cor. 6:16–17; Eph. 2:20–22; Rev. 21:2–4), the people, the possession, the Israel of God (Rom. 9:25; 2 Cor. 6:16; Heb. 8:10; 1 Pet. 2:9–10). The members of the church are called branches of the vine (John 15), living stones (1 Pet. 2:5), the elect, the called, believers, beloved, brothers and sisters, children of God and so forth. By contrast, those who are not really such are viewed in Scripture as chaff (Matt. 3:12), weeds among the wheat (13:25, 38), bad fish in the net (13:47), people without a wedding garment at the wedding (22:11), called but not chosen (22:14), bad branches in the vine (John 15:2), non-Israel though descended from Israel (Rom. 2:28; 9:6), evildoers who have to be put away (1 Cor. 5:2), vessels of dishonor (2 Tim. 2:20), such “who went out from us because they were not of us” (1 John 2:19), and so forth. All this makes it incontrovertible that in its essence the church is a gathering of true believers. Those who do not have an authentic faith may externally belong to the church; they do not make up its essential character. Though they are in the church, they are not the church…
Up to this point the meaning of the term “church” is plain and clear. But now we encounter two difficulties. The first consists in the fact that this scriptural concept of the church is applied to concrete, historically existing distinct groups of persons, in which there are always unbelievers as well. In the Old Testament, the entire nation was called the people of God, although far from everything that was called Israel was of Israel. In the churches of the New Testament, though to a much lesser extent, there was also chaff amid the grain and weeds among the wheat. And after the apostolic period, though the churches over and over became worldly, corrupt, and divided, we still call all of them churches. Theology, like Scripture, has at all times acknowledged this fact and, following Scripture, consistently stated that the basic nature of the church was determined by believers, not unbelievers. Augustine illustrated the presence of unbelievers in the church with the scriptural image of chaff and grain, or with that of body and soul, the outer and the inner person, bad “humors” in the body: in the body of Christ unbelievers are a kind of “bad humors.”111 Scholastic and Roman Catholic theologians spoke in similar terms. Bellarmine, for example, though he attempted to show that unbelievers are also members of the church, did not get beyond asserting that they are members “in some fashion”; they only belong to the body, not to the soul of the church. The good are the interior part of the church, the bad are the exterior part; unbelievers are “dead” or “arid” members, who are bound to the church only “by an external connection”; they belong to the kingdom of Christ as far as their profession of faith is concerned, but to the realm of the devil so far as it concerns their perverse lifestyle. They are children of the family on account of the form of their piety, but strangers on account of their loss of virtues. While there may not be two churches, there are in fact two parties in the church.113 And the Roman Catechism says that in the church militant there are two kinds of people, and that according to Scripture there are bad fish in the net and weeds on the field and chaff on the threshing floor, foolish virgins among the wise and unclean animals in the ark. In theory, this is not very different from the doctrine of the Reformation, but practically, things in the church looked very different toward the end of the Middle Ages. And Rome also consistently fosters the idea that external membership, a historical faith, observance of the commandments of the church, and submission to the pope constitute the essence of the church.
Rising up against this view, the Reformation posited the distinction between the visible and invisible church. Of nominal Christians Augustine had already stated that though they seem to be inside, they are separated from it by an invisible bond of love. Actually Rome cannot object to this distinction and does in fact itself accept it inasmuch as it distinguishes two kinds of people, two parties, in the church. Bellarmine speaks of “hidden unbelievers,”116 and Mohler praises Luther when he conceives of the church as a communion of saints and says that believers, the invisible ones, are the bearers of the visible church. But the distinction between the visible and the invisible church can be variously construed.118 The majority of these views, however, are to be rejected or at least do not come up for discussion in dogmatics. The church cannot be called invisible because Christ, the church triumphant, and the church that will be completed at the end of the ages cannot now be observed; nor can the church be called invisible because the church on earth cannot be seen by us in many places and countries, or goes into hiding in times of persecution, or is sometimes deprived of the ministry of the Word and sacraments. The distinction between the visible and invisible church can only be applied to the church militant and then means that the church is invisible with respect to its spiritual dimension and its true members. In the case of Lutherans and the Reformed, these two meanings have fused and cannot be separated from each other. The church is an object of faith. The internal faith of the heart, regeneration, true conversion, hidden communion with Christ (and so forth) are spiritual goods that cannot be observed by the natural eye and nevertheless give to the church its true character (forma). No human being has received from God the infallible standard by which one can judge someone else’s spiritual life. “The church makes no judgment concerning the most private things.” The Lord alone knows those who are his. Thus it is possible—and in the Christian church has always been a fact—that there was chaff amid the wheat and there were hypocrites hidden among true believers. The word “church,” used with reference to the militant church, the gathering of believers on earth, therefore, always and among all Christians, both Catholic and Protestant, has a metaphorical sense. It is so called, not in terms of the unbelievers who exist in it, but in terms of the believers, who constitute the essential component of it and determine its nature. The whole is called after the part. A church is and remains the gathered company of true Christ-believers...
[E]xternal membership, calling, and baptism are no proof of genuine faith. Many are called who are not chosen. Many are baptized who do not believe. Not all are Israel who are of Israel… [T]he church is conceived of as a gathering of believers. For it is genuine faith that saves persons and receives the forgiveness of sins and eternal life. While that faith is a matter of the heart, it does not remain within a person but manifests itself outwardly in a person’s witness and walk (Rom. 10:10), and witness and walk are the signs of the internal faith of the heart (Matt. 7:17; 10:32; 1 John 4:2). Granted, a person’s faith and witness are also often far from always in agreement. In the case of the children of believers, for example, there is faith that is not manifested in deeds, a confession that consists in saying “Lord, Lord” and is not born of true faith. Still, the advantage of defining the church as the gathering of believers over its description as the gathering of the called and the baptized is that it maintains precisely that on which everything depends, both for the individual and the whole church. Our being called and baptized is not decisive, for those who believe and are baptized will be saved, and, conversely, those who do not believe, even though they were called and baptized, will be condemned (Mark 16:16)…
What follows from all this is that we are limited to noting people’s witness and walk, and we neither can nor may judge their hearts. Unbelievers, therefore, no more constitute the essence of the visible church than of the invisible church. In neither of these respects do they belong to the church, even though we lack the right and the authority to separate them from believers and to cast them out. Even stronger: we can also say that the old Adam that still survives in believers does not belong to the church. This is not to agree with Schleiermacher when he locates the essence of the church in the operations of the Holy Spirit, for the church is not a gathering of operations but of persons. It is people who have been regenerated and brought to faith by the Holy Spirit, who as such, as new persons, constitute the essence of the church. Still, the church is a gathering of believers, and everything that does not arise out of true faith but from the old Adam does not belong to the church and will one day be cast out. For this reason the visible and the invisible church are two sides of one and the same church. The same believers are viewed in the one case from the perspective of the faith that dwells in their heart and is only known with certainty to God; and in the other case they are viewed from the perspective of their witness and life, the side that is turned toward us and can be observed by us. Because the church on earth is in process of becoming, these two sides are never—not even in the purest church—identical. There are always unbelievers within and believers outside the church. Many wolves are within and many sheep are outside the sheepfold. The latter occurred in the Old Testament, for example, in the case of Naaman the Syrian and is still true today of all who for one reason or another live outside the fellowship of organized (“instituted”) churches and yet have true faith. But all this in no way detracts from the fact that the essence of the church consists in believers alone.