“CHURCH” is a badly misunderstood word! It has come to mean something entirely different from what it meant to first century Christians.
In those days the term was used ONLY by Christians. The original Greek word for church, ekklesia, “called out” ek “out”, kaleo “to call”. The called out ones from the world.
THE BEGINNING OF THE CHURCH: It was founded upon the death, resurrection and ascension of Christ. And such an accomplished fact was not possible until Pentecost (Acts 2:1—47). There could be no Church until it was purchased with Christ’s precious blood (Acts 20:28).
Paul’s greetings to the churches: Romans16:5, “Likewise greet the church that is in their house.”
Colossians 4:15, “Greet the brethren who are in Loadicea, and Nymphas and the church that is in his house.” Philemon 1:1 “To Philemon our beloved friend and fellow laborer, to the beloved Apphia, Archippus our fellow soldier, and to the church in your house.”
So it is clear that a church is not a building but a group of people that are called by God out from the world.