Here is the quote for today:
However, a church was not a congregation of 5000, 2000 or even 200. Rather, the New Testament church was a fellowship of smaller churches. This didn’t mean that if there were twenty or thirty churches in a city that the church was fractured. The Apostle Paul often referred to the church in a city or region as one church—such as the church in Corinth. It was one church even though it met in many different places. Although Paul knew of various local churches in a city, he wrote one letter with the assumption that it would suffice for all the churches in the area. This dual pattern of church, or inter-church dependence, would continue for three more centuries until Constantine centralized Christianity through the institutionalization of the church.
These two expressions of church—local and city—facilitated the extensive growth and reproduction of the early church throughout the Roman world (cf. Acts 2:42ff; 5:42; 20:20). In the most basic sense, the church is an assembly of believers who are united together around the Lordship of Jesus Christ.
~ Jonathan Campbell, The Translatability of ChristianCommunity