The universal Church—the Body of Christ (Romans 12:5)—is composed of all true believers in Christ, and local churches are to be microcosm of the universal Church. As believers, we have our names written in the Lamb’s book of life (Revelation 20:12), and that is what is most important. However, it is also important to commit to a local church where we can give of our resources, serve others, and be accountable.
The Bible does not directly address the concept of formal church membership, but there are several passages that strongly imply its existence in the early church. “And the Lord added to them day by day those that were being saved” (Acts 2:47). This verse indicates that salvation was a prerequisite for being “added” to the church. In Acts 2:41, it seems that someone was keeping a numerical record of those who were saved and thus joining the church. Churches today that require salvation before membership are simply following the biblical model. See also 2 Corinthians 6:14–18.Church membership is important because it helps define the pastor’s responsibility. Hebrews 13:17 instructs, “Have confidence in your leaders and submit to their authority, because they keep watch over you as those who must give an account.” Whom will a pastor give an account for, except the members of his own church? He is not responsible for all the Christians in the world, only for those under his care. Likewise, he is not responsible for all the people in his community, only for believers under his leadership—his church members. Membership in a local church is a way of voluntarily placing oneself under the spiritual authority of a pastor.
Church membership is also important because, without it, there can be no accountability or church discipline. First Corinthians 5:1–13 teaches a church how to deal with blatant, unrepentant sin in its midst. In verses 12–13, the words inside and outside are used in reference to the church body. We only judge those who are “inside” the church—church members. How can we know who is “inside” or “outside” the church without an official membership roll? See also Matthew 18:17.
Although there is no scriptural mandate for official church membership, there is certainly nothing to prohibit it, and it seems the early church was structured in such a way that people clearly knew if someone was “in” or “out” of the church. Church membership is a way of identifying oneself with a local body of believers and of making oneself accountable to proper spiritual leadership. Church membership is a statement of solidarity and like-mindedness (see Philippians 2:2).