At a later time Paul established the truth in Ephesus, the chief city of Proconsular Asia. As might naturally be expected from the strategic position and political importance of that city, Ephesus also became an operative center for Christianity, "so that all they which dwelt in Asia heard the word of the Lord Jesus, both Jews and Greeks" (Acts 19:10). Thessalonica in Macedonia and Corinth in Achaia are other examples of the kind. [Sidenote: Regional units] The work of the church naturally fell into these geographical units; therefore the word "church" is sometimes used as a collective term designating a body of regional congregations. The church "throughout all Judea and Galilee and Samaria" (Acts 9:31), "the seven churches which are in Asia" (Rev. 1:11), "the churches of Macedonia" (2 Cor. 8:1), "the churches of Galatia" (1 Cor. 16:1). We must bear in mind, however, that this regional concept of the church was not an integral part of fundamental apostolic church government, but was merely incidental, the result of geographical location. In fundamental analysis distinctions are always drawn between things that are _different_, not between things of the same kind. These regional churches were not different kinds of churches; they were not bound together in separate groups by an external organization which placed a wall between them and other congregations of the saints. There was no authority here for the national-church theory nor for the sectarian church idea. Geographical separation there was, but not denominationalism. [Sidenote: Common bond of unity]