“Is the issue of membership in a local church addressed in the Bible? This is perhaps one of the most frequently asked questions about church membership. It may seem like a stretch to say that local church membership is a biblical concept—that is, until we actually start looking for it in the Bible. It’s not as pronounced as the atonement or justification by faith. But the evidence is there, and it is consistent.
The discipline case in 1 Corinthians 5 assumes public knowledge of who’s in the church and who’s not. ‘What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those outside. ‘Expel the wicked man from among you’ (W. 12-13, NW). Expelling makes sense only in the context of visible belonging. When Paul tells the Corinthian church to admit the man back into fellowship, he tells them, ‘The punishment inflicted on him by the majority is sufficient for him’ (2 Cor. 2:6, NIV). ‘Majority’ makes sense only in the context of a recognized whole.
We know that lists of widows were kept in the New Testament church (1 Tim. 5:9), and the Lord Himself keeps a list of all members who will inherit eternal life (Rev. 21:27). And God has always wanted a clear distinction to be made between the world and His holy people. One of the main reasons for the elaborate system of animal sacrifice and moral regulation in the Old Testament was to distinguish God’s people from the surrounding culture.
Church membership, then, is a means by which we demarcate the boundaries of the church. This is logically implied by the negative sanction of corrective church discipline. Corrective discipline assumes that it is important for a person himself to know that he is a member of the church. He can’t be expected to submit to the church‘s discipline if he is unaware of his own membership in the church. It also assumes that other members need to know whether or not a person is a member. If he’s being disciplined, then the other members need to know that is the case in order not to associate with him (1 Cor. 59-12; 2 Thess. 3:14-15). Further, corrective discipline assumes that it is important for those outside the church to know who the members of the church are, because one of the main motives for corrective discipline is the corporate testimony of the church in the unbelieving community.
Again, the evidence is not abundant. But it is clear, and it is consistent. At the very least, then we may say that local church membership is a good and necessary implication of God’s desire to keep a clear distinction between His own chosen people and the worldly system of rebellion that surrounds them. It was modeled in Corinth, and is still necessary for the purifying exercise of corrective discipline.”
-Mark Dever and Paul Alexander, The Deliberate Church – Building Your Ministry on the Gospel