The Bible speaks of only one church. Jesus said, “Upon this rock, I will build my church” (Matthew 16:18). That church established the first congregation in Jerusalem in 30 A.D. But it was not long before persecution came upon that congregation  “and they were all scattered throughout the regions of Judea and Samaria” (Acts 8:1). As they left Jerusalem, they started establishing congregations everywhere they went. After the gospel was given to the Gentiles (Acts 10), congregations started appearing in cities all over the world including Ephesus, Philippi, Rome, Corinth, and Athens to name a few. There were many local congregations, yet there was still one body, one church (Ephesians 1:22-23; 4:4). How could this be? We read the secret in Acts 2:42, “They were continually devoting themselves to the apostles’ teaching and to fellowship.”
Today there are MANY “churches.” Can all be the ONE church of the Bible? Of course not; if all the churches that exist today were the ONE church of the Bible, then God would be the author of confusion, which He is not (1 Corinthians 14:33). So how can a person KNOW the ONE church of the Bible? The answer is simple; compare that “church” to the apostles’ teaching, which is found only in the Bible.
Perhaps an example is in order. You will never find a church in the Bible with an organization reporting to an earthly head. If you see a church today with local churches reporting to a regional headquarters; and regional headquarters reporting to a national headquarters; and a national headquarters reporting to world headquarters with an earthly head; that is NOT the church of the Bible. You will never find such an organization in the Bible. Each local congregation in the New Testament was self-governed (they reported to no higher earthly organization); all of them together had one and only one SPIRITUAL head–Jesus Christ (Ephesians 5:23).
Why would a church do something different from what is in the Bible? Simply put, THAT church wants to continue in MAN’S teachings and NOT God’s teachings. Those “churches” might as well put a sign in front of their buildings that says, “The Church of Man.” The sign in front of our building says, “The Church of Christ” (Romans 16:16). We want to belong to Christ. We want to continue in the apostles’ teaching–the Bible teaching. What church do you want to belong to, God’s or man’s?