Yes, membership is biblical, except you won’t find an explicit command in the Bible to “join a church!” However, the Bible gives good indication that there was a way the early church knew who was a part of the church, and who wasn’t.
Further, God’s method has been to put his covenant people into covenant community. In the Old Testament, God made his covenant people into the nation of Israel. Israel was set apart and distinct from the other nations. In the New Testament, God puts his covenant people into the covenant community known as the church.
Because we see membership as biblical, it follows that membership is necessary. Here are some ways it is necessary and helpful:
First, ask yourself why? Did you have a bad experience in another church? Are you keeping the “back door” open just in case? Is your heart prideful and independent? Second, search the Scriptures and submit yourself to God’s Word. We encourage you to speak with an elder about your hesitations. Maybe there is something that can be cleared up.
No, however, it makes sense that only Christians are members.