Part of the problem is that the New Testament never really explains what a false church looks like. The first letter of John shows the difference between a true Christian and a false Christian. There are lots of passages that warn about and describe a false teacher. But a false church is never described. When Jesus addressed the seven churches in Revelation 2-3, He rebukes them for their ungodliness in heart and life and for their false doctrine, but he doesn't refer to them as false churches, even though some of the churches are almost dead and useless. Neither does Paul start pinning false church labels on churches that failed to meet the criteria of the Belgic Confession. These facts should make us exercise caution before we decree which church is false.
First, there are false churches in the world. The first mark of article 29 is right. Any church where the gospel is not preached is a false church. If a church doesn't teach people the Biblical way one must be saved from the wrath to come, then it can't be a true church. The main purpose of the church is to proclaim the way of salvation through faith in Christ, if it gets this wrong then what good is that church. It is no better than any cult or false religion. "As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed." Galatians 1:9
But the next two marks of a true church are where this confession goes wrong. Let's look at the second mark dealing with sacraments. Deciding if a church is administering the sacraments in the way Christ has instituted them is a bit subjective. The Reformed church would say that since Baptists and others don't baptize infants, then they are not a true church. But a Baptist reading this would say that Reformed people don't administer the sacraments rightly since they baptize babies and thus are a false church. Even within theological camps there are disagreements on the meaning and administration of the sacraments, that have lead to churches calling other church false for minor differences. The pure administration of the Lord's supper can be a subjective judgement as well that leads to calling each other a false church. What could be overlooked as a minor point of disagreement becomes a deep division due to the labeling of the other as a false church. Where there could be unity even though there are differences, by applying this mark of a true church, there is disunity.
Paul did not use this second mark of a true church either. He considered the Corinthian church to be a real true church. You can see that in the first chapter where he regards them as Christians in the church of God. Yet they had some serious misunderstandings in both doctrine and practice in regards to the Lord's Supper. Many were not eating it in a worthy manner. See chapter 11 for this. If Paul used the criteria of the Belgic Confession, then he could not refer to them as a true church, which he does. See 1 Cor 1:2
Furthermore, and this leads into the third mark of the true church, the same is true for church discipline. The church at Corinth didn't discipline sinning members. See chapter 5 for Paul's rebuke and instruction on this issue. So according to the Belgic Confession the church at Corinth failed on two of the three marks of a true church. Yet Paul still regarded them as a true church of God.
The third mark of a true church is supposed to be church discipline. But how can you measure this? Church discipline is the task of the whole church and it should be going on the whole time as members lovingly rebuke and correct each other. It is only at the final steps of church discipline that the elders get involved. What if only 75% of church discipline cases are being done, is that a true church? Truth is, I know Reformed churches that avoid member's sin at times or they take a very long time before any discipline actually happens. Are they then a true church?
In John 17:22-23 Jesus prayed for the unity of His church. "The glory which you have given me I have given to them, that they may be one, just as We are One; I in them and You in Me, that they may be perfected in unity, so that the world may know that you sent me, and loved them, even as you have loved me." Unfortunately Article 29 doesn't lead to unity in Christ's church. Therefore it is not a Biblical measuring stick for what is a true church. I believe there is a better way to evaluate churches without bringing unnecessary division. That is what I want to write about next time.