But the New Testament presupposes membership in several ways; by the words & phrases, pictures, and commands it uses in relation to the church. Consider the following examples:
Words & Phrases
“Yet none of the rest dared to join them” (Acts 5:13). After the death of Ananias and Sapphira, Luke tells us that “great fear came upon the church, and as many as heard these things” (v. 11). Because they were disciplined for their lie, the people realized that God was zealous for the purity and integrity of His church and it made them afraid. As a result, Luke says, “none of the rest dared to join them” (v. 15).
In this statement, the Greek term for “join” is κολλάω and has strong connotations of commitment and intimacy. The same word is used to describe someone being hired for a job (commitment) as when the prodigal son “joined himself” to a man who paid him to feed his swine (Lk. 15:15). Likewise, Paul uses this term to describe the “one flesh” unity resulting from sexual relations (1 Cor. 6:16-17), showing that this term carries the idea of great intimacy.
When Luke says that no man dared to “join” the apostles, the point is not that they refused to visit their meetings or listen to their preaching. Rather, the point is that they refused to make the same commitment to the congregation that other people had. In other words, the distinction in verse 11 between “the church” and “as many as heard these things” never went away, for the people in the latter group never joined the church.
“If the whole church comes together in one place” (1 Cor. 14:23). When the biblical writers use the phrase “the whole church” it indicates that there is a definite numeric value to the membership of each congregation. If this were not the case, then how could they know if the whole church was ever gathered together in one place? This argument is simple but forceful. Just as the phrase “the whole year” makes sense only if we know exactly how many days are in the year, so the phrase “the whole church” makes sense only if we know exactly how many people are in the church. It stands to reason that to identify the whole, half, or even part of the church means that some formal relationship had been established. Otherwise, it becomes an impossible task and the scriptural phrase loses its meaning.
Pictures of the Church
“But now indeed there are many members, yet one body” (1 Cor. 12:20). “And you are members of the household of God” (Eph. 2:19). The Bible uses many pictures and metaphors to teach us that the church is an institution with vertical and horizontal commitments. In each of these pictures, we learn that we are not to view ourselves merely as individuals united to the same entity, but united to one another as well.
For example, in the body the parts are not just “members of the body” (1 Cor. 12:12), they are also “members of one another” (Rom. 12:15). Likewise, in the household the parts are not just laid on the same foundation (Eph. 2:20), they are also “framed together” (v 23) and “built together” (v. 24) to form a holy habitation of God.
The implication of this horizontal unity is that church membership involves more than an abstract, invisible, and undefined relationship between you and God. Rather, membership in the body of Christ is a concrete, visible reality that can be known and seen, kept and broken, established and removed. It is a reality that exists between you and God, to be sure, but also between you and the other members of the church.
“Obey those who have the rule over you, and be submissive” (Heb. 12:17). “Shepherd the flock of God which is among you, serving as overseers” (1 Pet. 5:2). If you never join a church, it is impossible for you to “obey those who have the rule over you.” This is true for obvious reasons, one of which is that without the formal structures of membership in place, it is impossible to tell the difference between a member and a ruler.
A similar problem arises with the command for rulers to “shepherd the flock of God.” How can elders identify the particular flock that God holds them responsible for unless Christians formally align themselves with particular congregations?