Ironically enough, I don’t think I knew what church membership was until I went to a a big mega-church that told people on a regular basis that they didn’t need to become one. I had grown up with parents who functioned as committed members of their churches, but conceptually the idea of formal membership in a local body was foreign to me until a few years ago.

At the risk of over-generalizing, I think that’s about where your average American Christian (evangelical) is nowadays. Insofar as we’ve actually given any thought to the issue, we go to church, maybe plug in to a church, or at most commit to a church. But, formally belong to one? Like on a list? With like a signature and stuff? In our individualistic, consumeristic, anti-authoritarian society, that sounds too rigid, too formal, and just bizarre. The church is a family, a community where I go to get fed and built up in my faith, not some organization or institution I belong to.

For a while now I’ve been getting over that kind of knee-jerk, anti-institutional way of thinking. I mean, I’m at a Presbyterian church for crying out loud. Still, at the suggestion of a friend I finally picked up Jonathan Leeman’s couple of books on church membership and discipline (The Church and the Surprising Offense of the Love of God, Church Membership), and found his arguments challenging and largely persuasive. The issue is a big deal, and membership in the local body is far more central to being a Christian than most of us are used to thinking.

In one little section Leeman helpful summarizes a key section of his argument into 12 reasons membership in a local body matters:

1. It’s biblical. Jesus established the local church and all the apostles did their ministry through it. The Christian life in the New Testament is church life. Christians today should expect and desire the same.
2. The church is its members. To be a church in the New Testament is to be one of its members (read through Acts). And you want to be part of the church because that’s who Jesus came to rescue and reconcile to himself.
3. It’s a prerequisite for the Lord’s Supper. The Lord’s Supper is a meal for the gathered church, that is, for members (see 1 Cor. 11:20-33). And you want to take the Lord’s Supper. It’s the team flag that makes the church team visible to the nations.
4. It’s how you officially represent Jesus. Membership is the church’s affirmation that you are a citizen of Christ’s kingdom and therefore a pass-port carrying Jesus representative before the nations. And you want your representation to be authorized. Closely related to this…
5. It’s how you declare your highest allegiance. Your membership on the team, which becomes visible when you wave the flag of the Lord’s Supper, is a public testimony belongs to Jesus. Trials and persecution may come, but your only words are, “I am a Christian.”
6. It’s how you embody and experience biblical images. It’s within the accountability structures of the local church that Christians live and experience the interconnectivity of the body, the spiritual fullness of his temple, and the safety and intimacy and shared identity of his family.
7. It’s how you serve other Christians. Membership helps you know which Christians on planet Earth you are specifically responsible to love, serve, warn, and encourage. It enables you to fulfill your biblical responsibilities to Christ’s body (for example, see Eph. 4:11-16; 25-32).
8. It’s how you follow Christian leaders. Membership helps you know which Christian leaders on planet Earth you are called to obey and follow. Again, it allows you to fulfill your biblical responsibility to them (see Heb. 13:7, 17).
9. It helps Christian leaders lead. Membership lets Christian leaders know which Christians on planet Earth they will “give an account” for (Acts 20:28; 1 Pet. 5:2).
10. It enables church discipline. It gives you the biblically prescribed place to participate in the work of church discipline responsibly, wisely, and lovingly (1 Cor. 5).
11. It gives structure to your Christian life. It places an individual Christian’s claim to obey and follow Jesus into a real-life setting where authority is actually exercised over us (see John 14:15; 1 John 2:19; 4:20-21). It’s God’s discipling program. 
12. It builds a witness and invites the nations. Membership puts the alternative rule of Christ on display for the watching universe (see Matt. 5:11; John 12:34-35; Eph. 3:10; 1 Pet. 2:9-12). The very boundaries, which are drawn around the membership of a church, yield a society of people that invites the nations to something better. It’s God’s evangelism program. 

–Church Membership: How the World Knows Who Represents Jesus, pg. 79-81

Membership matters then–a whole lot more than most of us are used to acknowledging. The local body is key to mission. It’s key to discipleship. It’s key to actually following Jesus instead of just claiming to.

For the unconvinced, I’d recommend picking up Leeman’s little, and I mean very little book, and examining the biblical arguments for yourself. (If you’re up to it, I highly recommend his bigger book.) Even if you don’t come away convinced of every point, you’ll be challenged to take a deeper view of what it means to be a part of the body, the Church.

Soli Deo Gloria