Steve Hays has posted a fine way to think about the community of Jesus followers with the illustration of vehicles and those who take them.
What is the best way to formulate the abstract idea of “church” that will be in concert with the ideas of “members of one body” (1 Cor. 12.12), “living stones” comprising a spiritual house (1 Peter 2.5), and the various agricultural motifs such as branches bearing fruit (John 15 and others) or wheat with grain (Mt. 13 .1-9 and others)?
A common allegation of Catholic and Orthodox apologists is that their church is the original church. It goes straight back to Christ, whereas Protestant churches are upstarts. These didn’t pop into existence until the 16C.One problem with that allegation is that it’s only as good as your paradigm of the church. Put it this way, do you define the church by the vehicle or the passengers?How does the NT describe the church? As the community of faith. A fellowship of believers, and families of believers. They are united by the grace they share and their common faith in the message of Scripture. In addition, there’s a minimal polity (elders, deacons) and at least two sacraments (baptism, communion).Basically, the NT defines the church by the passengers, not the vehicle. If the identity of the church is centered on the passengers rather than the vehicle, then the church can exist continuously even if the vehicle changes, just as passengers can change vehicles, but remain the same passengers.The church as passengers goes back to NT times. Indeed, God has always had a community of faith. Protestants can trace the church back as far as you please. In the Reformation, they changed cars.