Jesus established the church as a public institution to display the good news about Himself and His work (John 17:21, 23). To that end, He granted it the ability to draw a line between who was “in” and who was “out.” Verses like Matthew 16:19 and 18:18 and John 20:23 make clear that He expected the apostles, and the churches they organized, to be able to guard the Gospel and exclude those who do not live in line with the Gospel.

Acts 20:28 refers to a local congregation as a flock of sheep. A flock is made up of specific sheep. 1 Peter 2:5 likens the church to a building. A building is made up of distinct, individual bricks. In fact, the word “members” is actually used in Paul’s extended metaphor of the church as a body in 1 Corinthians 12-14. This does not just mean the universal Church in which all Christians are included. A body is a specific, local organism. So, Paul here is talking about Christians as members of a local church body. For a church to function like a body, it needs to be clear who is a member and who isn’t. Your arm doesn’t just decide to leave anytime. It’s clearly connected to your body.

In 1 Corinthians 5 Paul declares that Christians should judge those inside the church, and expel those who refuse to repent. To formally exclude someone, you must first formally include them. The same applies to Jesus’ words concerning discipline in Matthew 18. Paul writes in 2 Corinthians 2:6 that a Christian has been punished by “the majority.” For there to be a majority, you have to have a definite set of people in which the majority is included.

Hebrews 13:17 tells us our pastors are tasked with “keeping watch over [our] souls” and that they are going to have to give an account to God for that. Thus, becoming a church member is a great act of love and submission to our pastors because it enables them to know very clearly for whom they are accountable.

In the same way that a wedding covenant displays a higher and better level of commitment than just “shacking up,” so formal membership provides a more visible commitment to Christ. Think of it as similar to a wedding ring; it makes a very clear statement about your identity as a Christian.

It is immensely comforting to know that if I fall into sin in an area of my life, there are other members who are committed to keep me accountable, and will exclude me from the church if necessary. While that may sound harsh, Scripture is clear about the depth of my sin and the necessity of having other believers keeping an eye on me so that my heart doesn’t become hardened by sin (Hebrews 3:12, 13).

“By identifying ourselves with a particular church, we let the pastors and other members of that local church know that we intend to be committed in attendance, giving, prayer, and service. We allow fellow believers to have great expectations of us in these areas, and we make it known that we are the responsibility of this local church.” – Mark Dever