There are three basic Bible texts relating to the keys of the kingdom: Matt. 16:16-18, Matt. 18:15-20, and John 20:21-23. These three texts have been understood and applied by the church as we find it in Lord's Days 30 and 31 of the Heidelberg Catechism.
It is clear that Christ's use of the phrase " keys of the kingdom of heaven " represents an image or metaphor. Much has been written about the background of this image, but it is clear that Jesus here teaches us that the kingdom is an enclosed place with doors or gates requiring keys for admission and for exclusion. It is also clear that Christ gives the keys of the kingdom to his disciples/apostles, and via them, to His church, especially represented by the office of elder (cf. LD 30, Q. & A. 82).
The H.C. clearly teaches that the two keys of the kingdom are preaching and church discipline. While we will come back to the key of preaching later, it is best to begin with the key of discipline as outlined in the catechism in order to understand how it relates to closed communion.
In Q. & A. 82, the keys are referred to in the context of excluding from the sacrament (of the Lord's Supper) those who either by confession or life show they are unbelieving and ungodly. Then in Q. & A. 85, the key of discipline is described in terms of closing and opening. In the case of those who show themselves to be un-Christian in doctrine or life, the key of discipline eventually leads to being forbidden the use of the sacraments and finally to being excluded from the church-excommunication. Thus, the key of discipline is used negatively; this is how the kingdom is "closed."
It is important to notice here how the key of discipline is directly related to exclusion from the Lord's Supper which is a foretaste of the ultimate sanction of excommunication. After all, excommunication is really nothing more than making permanent what was only temporary when the sinner was first excluded from participation in the Lord's Supper.
Q. & A. 85 also teaches us a positive use of the key of discipline. When an excommunicant repents, he is again received back into the church, and by implication allowed again to partake in the Supper. This is how the key of discipline "opens" the kingdom.
While the context of the catechism is clearly one of discipline, we are not wrong to draw some conclusions about the use of the keys that show that their application is a bit wider. For example, when someone from the world believes the gospel and repents, he seeks to identify himself with Christ's church. When he shows that he believes the gospel and is living a godly life consistent with such a profession, the elders of the church admit such a person as a member of Christ's church and hence to the sacraments (in this case, both baptism and the Lord's Supper).
This pattern is reflected explicitly in the Form For the Public Profession of Faith (p. 593). There a direct connection is made between covenant youth professing their faith and admission to the Lord's Supper: "We acknowledge His love and power, by which He instills in His children the desire publicly to profess their faith in Him in the presence of His holy church, so that they may receive admission to the holy supper."
This same pattern is implicit in the Form For The Baptism Of Adults. While there is no explicit reference to such a person being admitted to the Lord's Supper, it is clearly implied, and universal practice testifies to this. Indeed, it should be clear that from the visible, organizational aspect of the situation, there is no other means by which it is known publicly (other than verbal announcement) that a person is indeed a member of Christ's church other than continuing participation in the sacrament of the Lord's Supper.
Based on the above analysis, we can conclude that when the elders of the church admit a repentant outsider into the church and to the Supper, they have exercised a key of the kingdom. We can go further and rightly say that every time a member of the church partakes of the sacrament he does so by virtue of the authority of the keys vested in the elders administering the sacrament. For while the emphasis in the catechism on the key of discipline is negative-who is to be excluded and why, we should not overlook the positive side-who is to be included. Implicit here is the fact that the elders have oversight in the congregation. This oversight began with doctrine and life, and continues with those same two criteria. Hence, when members are not excluded from the sacrament, due to sins in doctrine and/or life, they are allowed or included precisely because the elders have determined that doctrine and life are scriptural. In short, if the elders have the authority and duty to exclude under some circumstances, they, by implication, clearly have the authority and duty to include or admit under other circumstances.
The analogy of the key of preaching may be helpful in understanding the above. In Q. & A. 84, the catechism states: "According to the command of Christ, the kingdom of heaven is opened when it is proclaimed and publicly testified to each and every believer that God has really forgiven all their sins for the sake of Christ's merits, as often as they by true faith accept the promise of the gospel." How often is the kingdom of heaven opened by the key of preaching? Every Lord's Day-"as often as .!" By analogy, we may say that the kingdom is opened by the key of discipline also "as often as" members are admitted on proper grounds to the Supper.
By the way, it should be noted that this discussion of the role of the elders in admitting and excluding people to the sacrament is not to be confused with what we find in Q. & A. 81. There we find a description of those who are to come to the Table, and the criteria listed are the same as the three parts of self-examination found in the Form for the Celebration of the Lord's Supper. The key words are "self examination." Members of the church engage in such self-examination in their hearts and it is known only by them. The overseeing elders can only observe and know what is public-what people say (doctrine) or do (life), not what is in their hearts. Hence, we may rightly conclude that there are in reality two tests for admission to the Table: the first is the one conducted by the elders when they determine that the public doctrine and life of the member are scriptural; the second is the one conducted by the individual-the self-examination. We must be careful not to confuse or conflate the two steps, and they must not be seen as mutually exclusive, but rather complimentary since both reflect aspects of Biblical truth.
In summary, we may say that while the catechism focuses our attention in a negative context of discipline on the use of the keys, we are not amiss to also stress in the proper context the positive side or use of the keys-the opening or loosing.
If we understand that the administration of the Lord's Supper thus involves the authority of the elders and the use of the keys of the kingdom, then we are able to easily see how this same authority and use of the keys relate to the admission and exclusion of visitors.
First, we must be again reminded of the inherently closed nature of the church and the kingdom of heaven. People are not allowed to freely stroll in or out on their own recognizance. Christ has promised His kingdom to believers only, and he has granted a structure of authority in the opening and closing of the gates of the kingdom.
In this context, we may rightly understand how visitors or guests are to be treated in relation to the Lord's Supper. First, however, it must be seen that in the nature of the case, the administering elders do not have oversight of the guest. Hence, they cannot know if the guest meets the essential criteria in doctrine and life (this assumes for now that interviews with visitors are fatally flawed because of self-testimony). However, there is a way for the administering elders to gain the necessary information to determine the qualifications of the visitor, namely, the visitors own elders who have been appointed by Christ to oversee that person. Only those elders have the right and duty to know if such a person has the proper doctrine and life.
How is such official (because it comes from Christ's office bearers) information about a visitor to be elicited? We have provided a method for this in Art. 61, C.O. which is written attestations. We need not quibble about written attestations as though there is something sacrosanct about writing on a piece of paper. Indeed, the same information could be obtained by other media given the electronic means available in our day. However, it is important to understand that the Biblical pattern of official attestation is the testimony of at least two relevant parties-in this case the elders of the visitors. In this light, it is easy to see why merely getting verbal testimony from friends or acquaintances of the visitor is inadequate. Not only are they not the proper authorities, but it may also be that the visitor in question is under unannounced censure at the moment (visiting ministers are in a separate category by virtue of their public office and the practice of immediately notifying sister churches if the good standing of such a person should change).
A further element in Art. 61, C.O. is that the visitor
must be from one of our sister-churches (I will not digress here on the entirely
erroneous notion that this part of the article thus allows members of non-sister
churches to be admitted on other grounds!).
This is important because it ensures that the standard used to measure doctrine and life in the administering church is the same as that used in the church of the visitor. In other words, if we have a visitor from a church that does not profess the Reformed faith and regulates life by a skewed set of values, then obtaining an attestation from such overseers throws into confusion and contradiction the whole point of oversight. Integrity in ecclesiastical relationships is hence integral to a consistent application and use of the keys of the kingdom with regard to visitors.
It should be clear by now that admitting and excluding guests to the Lord's Supper is every bit a part of the authority of the administering elders as admitting and excluding their own members. This is an exercise of the keys of the kingdom of heaven. Furthermore, there is the duty to keep the Lord's Supper holy in accord with the very significance of the sacrament itself, namely, Christ's death for the sins of His people.
It should also be clear by now that the notion that unbelieving our ungodly visitors are somehow to be equated with hypocrites (as explained in Q. & A. 81), and hence excluded from the knowledge and authority of the elders is completely erroneous. If such a view were correct, then one could easily argue that no fencing of visitors is necessary at all. First, all visitors who were believing and godly would be acceptable anyway. Second, visitors who were unbelieving and ungodly could come based on the ignorance of the administering elders-they must be treated as virtual hypocrites who, Q. & A. 81 says, do come to the sacrament. On this basis, there would be no need for any article like Art. 61, C.O., and it would make nonsense out of the use of the keys of the kingdom.
In light of the above, it can be seen that Art. 61, C.O. is more than just a convenient rule, chosen from among many possibilities, that we have adopted in order to deal with this situation. In fact, we should note the title given to this article: "Admission to the Lord's Supper." Our forefathers who authored this Article were here clearly seeking to faithfully implement the principles outlined in L.D. 30 and 31 of the catechism. This is why Art. 61 cannot be equated with, say Art. 55, that speaks about the number of hymns to be sung. The former reflects Scriptural principles; the latter does not.
The above view of the use of the keys in relation to both members and visitors makes closed communion clear. It should help to make clear why we are troubled by establishing ecclesiastical fellowship with churches that either practice an explicitly open communion, such as the PCK (by their own admission) and the OPC, but also those churches, such as the URC and RCUS that don't faithfully implement the principles in LD 30 & 31 in the administration of the sacrament to visitors.
In the case of the URC and RCUS, their rules allow for
visitors from non-Reformed churches. There is a lack of ecclesiastical integrity
for visitors are not required to be members of churches with whom they have
established ecclesiastical fellowship. Thus, all the problems outlined above
come into view (differing standards for determining what is proper doctrine
and proper life). Furthermore, their rules for administering the sacrament to
guests rely almost exclusively on self-testimony rather than official attestation,
thus undermining the pattern of authority that Christ himself set in His church.