The Bible says a Christian without a church home is like an organ without a body, a sheep without a flock, or a child without a family. It is an unnatural state. The Bible says, "You belong in God's household with every other Christian." (Ephesians 2:19b LB)
Today's culture of independent individualism has created many spiritual orphans - "bunny believers" who hop around from one church to another without any identity, accountability, or commitment. Many believe it is possible to be a "good Christian" without joining (or even attending) a local church, but God would strongly disagree.
The church is so significant that Jesus died on the cross for it. "Christ loved the church and gave his life for it." (Ephesians 5:25 GW)
Except for a few important exceptions referring to all believers throughout history, almost every time the word church is used in the Bible it refers to a local, visible congregation. The New Testament assumes membership in a local congregation.
A church family identifies you as a genuine believer. I can't claim to be following Christ if I'm not committed to any specific group of disciples. Jesus said, "Your love for one another will prove to the world that you are my disciples." (John 13:35 NLT)
When we come together in love as a church family from different backgrounds, race, and social status, it is also a witness to the world. (Galatians 3:28)