It’s obvious that the early church knew its flock well. In Acts 20, Paul exhorted the elders of the Ephesian church to faithfully watch over and shepherd their people. But it’s very difficult to shepherd if you don’t know who your flock is. And sheep don’t survive well just roaming around on their own.

While the New Testament never speaks of church membership in today’s terms, the principles of life in the early church lay the foundation for faithfully submitting and belonging to a local congregation. While the original membership process might vary from today’s patterns, there’s no doubt that New Testament Christians were lovingly united and bound to their local body of believers.

While the church was being born during Peter’s sermon on the day of Pentecost, Acts 2:41 says, “So then, those who had received his words were baptized; and that day there were added about three thousand souls.”

Added to what? Added to the others. What others? Acts 1:15 says that about one hundred and twenty people were already gathered together in the upper room—the three thousand people saved on the day of Pentecost would have been in addition to the core that already existed after Christ’s ascension.

It’s possible their names were even physically added to a list by a secretary or someone keeping track, but that’s not what is most important. The moment these men and women were saved, they were baptized as a physical testimony of their transformed lives and as a way to identify with the other believers. They were immediately welcomed into the church.

Just a few verses later, Acts 2:47 says, “And the Lord was adding to their number day by day those who were being saved.” The influx of new members didn’t stop at Pentecost. The church met daily, and every day the Lord was drawing new men and women to Himself and into fellowship with His people.

That explosive growth wasn’t short-term. A few chapters later, in Acts 5:14, the church was still growing exponentially: “And all the more believers in the Lord, multitudes of men and women, were constantly added to their number.” The implication is that someone was keeping track of the ever-expanding size of the flock.

Of course in the earliest days of the church, everyone met together. After Stephen was murdered, believers were scattered by persecution. A church started in Antioch, and then others began through the ministry of Paul. Eventually the church extended in all directions through the apostles’ missionary endeavors. What began with one massive congregation was now reproducing itself from city to city as the teaching of the gospel spread and new men and women were saved.

But no matter where they were being saved, the implication is always that they were immediately welcomed into a local gathering of believers. In fact, any time someone moved or relocated, they brought with them or were preceded by letters of recommendation to their new congregation. Acts 18:27 describes how Apollos was commended to the church at Achaia by the disciples. It would have been typical to notify the church receiving him that he came with the blessing of his previous congregation.

Paul followed the same pattern. In Romans 16:1-2 he wrote,

I commend to you our sister Phoebe, who is a servant of the church which is at Cenchrea; that you receive her in the Lord in a manner worthy of the saints, and that you help her in whatever matter she may have need of you; for she herself has also been a helper of many, and of myself as well.

Phoebe’s journey to Rome was no accident—it’s likely she was the one who delivered Paul’s letter to the church there. So at the end of his passionate epistle, Paul paused to make sure she was looked after and cared for by the believers in Rome. He was eager to keep track of his sheep, letting the other congregation know her faith was genuine. It was a pattern he repeated with other epistles as well.

And with good reason—the early church was very concerned to maintain its purity and to keep the tares out. There were many factious, heretical, sinful people who posed an immediate threat to the church. As genuine believers moved from place to place, authenticating their faith and their character helped protect the church from error, division, and corruption.

That protective attitude is appropriate. The Lord loves His church—He shed His blood and died for His church. We are His body in this world as He works through us to accomplish His will. And we are His bride in eternity, the object of His affection and love. He demands a chaste and pure bride. He wants the church to be all it should be.

One of the key ways the church can guard itself from error and maintain its purity is to confirm the faith of its people and keep them accountable. The early church didn’t have a name for that—they didn’t need one. Today we call it church membership.