The following was presented as a lecture for the “Faith Seeking Understanding” course of the Partnership for Theological Education in Edinburgh on Tuesday.

Ecclesiology, or the study of the church, is perhaps one of the most difficult and elusive areas of theology, despite the fact that its content seems so empirically obvious.  With soteriology, the doctrine of salvation, we are dealing with things that happen largely invisibly within us, and in some vague future judgment.  With eschatology, the doctrine of “the last things,” we are dealing with things entirely future, and largely hidden from our perception.  But the object of ecclesiology, “the church,” is right in front of us, all around us, right?  We see numerous churches as part of our normal experience, and “the church” can simply be described as the totality of these, the whole body of those who call on the name of the Lord—right?

This apparently simple description, however, becomes more complicated when we try to relate the rather messy empirical reality of churches as we find them to the rather exalted language that Scripture often uses in speaking of the Church.  And indeed, given the importance of the church, Scripture is remarkably elusive in how it speaks of this fundamental Christian reality, resorting almost entirely to a rich array of metaphors which seem to bear little obvious relation to one another.  I borrow the following catalogue from Herman Bavinck:

the church is the body of Christ, the bride of Christ, the sheepfold of Christ who gives his life for the sheep and is known by them, the building, the temple, the house of God, built up out of living stones on Christ as the cornerstone, and on the foundation of apostles and prophets, the people, the possession, the Israel of God.  The members of the church are called branches of the vine, living stones, the elect, the called, believers, beloved, brothers and sisters, children of God and so forth. (Reformed Dogmatics IV.298)  

What are we to make of all this?  We might seek to gain some illumination from the Old Testament, seeing, as Christian theology has frequently done, the church as the New Israel, the continuation or rather fulfillment of the people that God called out of Egypt, and who worshipped him in the centuries before Christ.  But the discontinuities between the church and Israel seem to loom as large as the continuities: Israel was at the same time a political state, whereas the church makes no such pretensions, but lives amidst, though distinct from, the political states of the world, even when such states confess Christ; Israel had at the center of her identity one geographical location, whereas the church is called to be spread over all the world; Israel had detailed and specific laws governing her worship and religious identity, whereas the church does not.  These discontinuities mean that although important to helping us construct a doctrine of the church, the Old Testament will hardly relieve our difficulties in that task.  

We cannot take refuge either in some kind of ecumenical consensus, as we can in many other areas of theology.  Despite the great differences between different churches—Catholic, Orthodox, many brands of Protestant—we can often succeed in describing the basic essentials that we all share in common.  That is not so easy with the doctrine of the church, for it is of course in large part the fact of different doctrines of the church that forces the continued separation of different churches.  The Catholic Church in particular is defined largely by her understanding of herself, of what it is to be the Church, and Protestants differ from that not merely in a few particulars but largely in essentials.  Instead, then, of trying to tell you straightforwardly what the church is, I will seek to sketch the sorts of tensions which a coherent theology of the church has to navigate, and offer a very brief historical overview of how different ecclesiologies have developed in response to these tensions.  

Not of the World yet In the World: On the one hand, the church is to be discernibly separate from the world; on the other hand, the church is to be in the world, and engaged with it.

Holy yet Mixed: On the one hand, the church is the body of those united to Christ, heirs of salvation, and yet the church contains hypocrites, sinners, apostates.

Universal yet Particular: On the one hand, the church is supposed to be a universal body throughout the world, and yet the church comes to proper expression only in the life of individual congregations. 

United yet Diverse: Related to this, on the one hand, the church is supposed to be one—united in Christ, in one faith, one baptism; on the other hand, the church is clearly not united—there are different churches which are not in agreement with one another and which do not necessarily practice the sacraments the same, acknowledge one another’s sacraments, or share the same institutional structure.

Structured yet Equal: On the one hand, the church needs leaders—clergy—who have a special role to play; on the other hand, all Christians are equally members of the church.

Instrument of yet Response to God: On the one hand, individuals come to Christ through the ministry of the Church; on the other hand, it is only God who saves, and the church can only comprise a human response to his action.  

Social yet Composed of Individuals: On the one hand, we are to experience and live out our Christian identity socially, within the church, a new people; on the other hand, each Christian has a personal relationship with Christ, not merely a horizontal relation with other believers.

In its earliest days, many of the above tensions lay largely concealed beneath the surface, and ecclesiology might seem relatively straightforward.  In particular, there was little difficulty with the first, differentiating the church from the world—the wider society was not Christian, and actively persecuted the church.  If you were a member of it, you were dedicated, and were noticeably different from those outside.  Moreover, the second, the gap between sincere and faithless members was not too much of a problem, even if it could not be altogether avoided, since only those really dedicated joined the church, and if they failed to maintain the faith or the discipline, they were excluded.  Although there were many different individual churches, the third issue, and although they in fact differed from one another considerably in liturgy and teaching, the fourth, early Christians were able to think in terms of one unified church, because each church was generally only in direct contact with its near neighbors, so regional variations did not loom very large.  There were totally independent churches outside the Roman empire, but these were largely unknown to those within the empire.  The fact that the Scriptures were of course not widely available, and that the wider society was hostile to Christianity, meant that as a matter of fact, no one came to Christ except through and within the Church, so the sixth tension did not loom very large;  Early Church Fathers could thus confidently pronounce extra ecclesiam nulla salus est—“outside the church there is no salvation.”  Of course, as theological divisions arose within the early Church, and threatened to destroy its unity, it did seem increasingly important to distinguish the true church from its rivals.  Partly because early heresies tended to err in the direction of what we might call the charismatic (in which each believer had his own direct conduit to the Spirit), the tighter definition of the church took place particularly by stressing on the Structured end of the “Structured but Equal” tension.  It was the ordained bishops, particularly those who could claim a direct connection to the apostles, who ensured that the church was truly the church.  Ordinary believers, then, were essentially dependent on these for their connection to the church, which risked overemphasizing the church as mediator of God’s action, rather than response to it.  

These trends, and other such changes, were not begun, as many have claimed, with the conversion of Constantine and legalization of Christianity in the early 300s, but this did accelerate them in an important way.  Those events rendered it suddenly difficult to show how the church was separate from the world at large, since it seemed suddenly quite at home in it, and respected by it.  Since it no longer took such dedication to become a Christian, many half-hearted believers joined the church, who didn’t seem to be true believers at all—the church seemed much more mixed than holy.  Moreover, the unity of the church was much more strongly challenged.  Freed from persecution, able to focus more on secondary matters, and able to communicate much more freely throughout the empire, Christians started to realize that quite significant differences separated them from others.  They sought to codify the unity of the Church in its subscription to particular creedal documents, but this simply raised the question of whether those Christians who did not subscribe, but who nonetheless professed faith in Christ and practiced the sacraments, were in fact Christians.  As larger groups divided over doctrinal differences, it was not mere possession of a bishop that ensured communion with the church; the bishops themselves must be in communion with the orthodox patriarchs, and eventually, the pope.

This increasing stress on the institutional structure of the church, and on the clergy as the specific locus of the identity of the church, also helped to resolve the problem of distinguishing the church from the world.  The clergy were increasingly distinguished from other Christians not only by their dress but by their way of life, although it was not till the 11th century that celibacy was enforced for all clergy, and then only in the West.  Medieval theology came to distinguish between the “teaching church” (the clergy) and the “learning church” (the laity), and emphasized the priority of the former.  Struggles between lay and ordained Christians in the Middle Ages are often characterized by historians as struggles between “church” and “state,” demonstrating the extent to which, in the new ecclesiology, only the clergy properly comprised the church.  Combined with the earlier understanding that it was in and through the church that we are brought to salvation, this meant that ordinary Christians were dependent on the clergy as mediators of their salvation.

The Reformation, in reacting against the understanding of salvation this created, involved at the same time a dramatic revolution in ecclesiology.  Central to this revelotion was the Protestant emphasis on the Word of God as that alone which brings spiritual life.  The church, for Protestants, was not first the guardian of the Word, but the creature of the Word.  This doctrine meant that the Reformation tended to emphasize the other side of the seven polarities we described above—individual salvation by Christ as primary, and horizontal fellowship as secondary; Christ as the author of redemption, and the church as a response to Him; the priesthood of all believers, whether ordained or lay; the relative identity of church and world in their visible expression; the mixed and imperfect character of the church in history; the priority of particular congregations over the universal church; and the acceptability of diversity within the visible church.

However, both sides of each polarity were maintained in the Protestant dialectic between the church visible and the church invisible (properly speaking two aspects of one church, rather than two churches, though this distinction proved hard to maintain.)  This invisible/visible distinction had been present in Catholic theology as well, but it became much more important for the Reformers.  Although the church was properly identified as the body of believers, the communion of saints, those who clung to Christ, it was not visible precisely who these were, since hypocrites and unbelievers would always be mixed in.  The Church was visibly in the world, and yet its identity was “hidden with Christ in God,” outside the world, in the words of Paul.  Just so, as visibly seen, it was diverse and often divided, yet invisibly in Christ, one and united.  In its visible form, it required structure, and pastors, and perhaps bishops, and these were responsible for bringing the word and the sacraments, the means of salvation, to believers; and yet, at another level, ministers were every bit as dependent on Christ alone for salvation as their flock, and all had equally the power to judge the Word and derive life from it.  As a visible body, the church was a society, constituted by horizontal relationships, yet invisibly, each true member of that body was uniquely united to Christ.

This account, however, seemed too elusive for many, creating a temptation to pin down more precisely “the true church.”  This temptation took two forms.  On the one hand, some tended to separate out the visible and invisible aspects into two churches, and to identify the latter as the “true church.”  On this account, the visible body and institution became quite dispensable, and Christianity could become entirely individualized.  Many Protestant movements, particularly in the last century, have gone in this direction.  However, the other temptation was perhaps stronger in the early days of Protestantism, in which many tried to define which visible churches could be identified as “the true church”, by identifying those which manifested most fully the qualities of the invisible church—particularly its holiness and purity.  The Anabaptists went furthest in this direction, attempting to return to the days before Constantine, when the church was visibly separate from the world, even though that “world” now consisted of other professing Christians.  This meant identifying the church by its adherence to gospel laws of holy living, which could lead to a kind of legalism.  

More mainstream Protestants sought to solve the problem with the doctrine of the “marks of the church.”  Originally, they described just two marks, the word and sacrament.  Many soon added a third mark, church discipline, by which ungodly living was excluded from the church.  However, it quickly became necessary to qualify all of these—the word purely preached, the sacraments rightly administered, discipline biblically practiced.  In many cases, in trying to define these more precisely, Protestants emphasized that it was only the rightly ordained ministers who ensured a pure word, sacrament, and discipline, which could lead to the conclusion that it was the clergy that constituted the true church, much as Catholicism had taught.  To avoid this conclusion, most of the best Protestant teaching has backed away somewhat from the doctrine of the “marks of the church,” emphasizing that these only serve to point, broadly, to where the church is to be found, not to delineate precisely its boundaries.  The quest to distinguish “the true church” from “false churches” has generally proved to be a dead end, and it has proven more fruitful to talk in terms of better and worse churches, truer and falser, with no church perfectly pure, and no church (as an assembly that professes faith in Christ) perfectly corrupt, at least so far as our eyes can see.