There were other churches in Asia at the close of the first century. The NT itself refers to congregations at Troas (Acts Acts 20:5-12), Colosse (Col. Col. 1:2), and Hierapolis (Col. Col. 4:13). There might also have been churches at Magnesia and Tralles, since Ignatius wrote to them less than twenty years later.2The question naturally arises as to why Jesus chose these seven churches from among all the churches in the region? And why seven? The answer to the first question would seem to be found in their geographical distribution which facilitated communication by letter along the established trade routes between the cities:
Ephesus was the messengers natural place of entry to the mainland of the province of Asia, and the other cities lay in sequence on a circular route round its inner territories. it may readily be supposed that a regular itinerary had been perfected since Pauline times and that the seven focal cities on the route had acquired a special importance as organization and distributive centres for the church of the area.3
It is not at first sight easy to explain the principle on which the Apocalyptic list of seven has been formed. Why does it include two comparatively small towns, Thyatira and Philadelphia, while Tralles and Magnesia, Hierapolis and Colossae, Alexandria Troas and Adramyttium, Miletus and Halicarnassus, Dorylaeum and Synnada, are passed by? Some at least of these cities had Christian communities before the end of the first century; . . . the first three cities in St Johns list were by common consent primary cities in Asia, and they stand in the order which would normally be followed, at least by a resident at Ephesus. Moreover Ephesus, Smyrna, and Pergamum were in direct communication with one another by the great road which the Romans had constructed shortly after their occupation of Asia. So far then both the selection of the names and their order are easy to understand. But why should not the Apocalyptic messenger have been sent on from Pergamum to Cyzicus or to Troas? Why was his course at this point diverted to the inland towns of Thyatira, Sardis and Philadelphia, . . . all the Seven Cities stand on the great circular road that bound together the most populous, wealthy, and influential part of the Province, . . . Planted at these seven centres, the Apocalypse would spread through their neighbourhoods, and from thence to the rest of the province.4As to why seven churches were chosen: the symbolic meaning of seven indicates completeness or perfection. It appears to be a deliberate choice, like the many other occurrences of seven in the book of Revelation, to signify that these seven churches typify all churches in every age.
1 There were other churches in the Asian province: Colosse, near Laodicea, to which Paul wrote in one of his epistles; Troas, where he held a meeting and restored Eutychus to life (Acts Acts 20:5-12); Magnesia and Tralles, to which Ignatius indited letters at the beginning of the second century. Colosse and Troas were certainly founded before the writing of the Apocalypse, and probably the others were also.Merrill C. Tenney, Interpreting Revelation (Peabody, MA: Hendrickson Publishers, 1957), 29. There were more than seven churches in the region meant by Asia, for instance, Magnesia and Tralles.A. R. Fausset, The Revelation of St. John the Divine, in Robert Jamieson, A. R. Fausset, and David Brown, A Commentary, Critical and Explanatory, on the Old and New Testaments (Oak Harbor, WA: Logos Research Systems, Inc., 1997, 1877), Rev. 1:1.
3 Colin J. Hemer, The Letters to the Seven Churches of Asia in Their Local Setting (Grand Rapids, MI: William B. Eerdmans Publishing Company, 1989), 15.