What warning did the Ephesus assembly receive about Roman authorities?

Les explains that Ekklesia means a called-out assembly and does not necessarily imply pastors, bishops, and deacons, though Paul does use it for the Body of Christ in the local church. He cites Acts 7, where Stephen spoke of the Church in the wilderness—not a Church, but a called-out assembly, because God called Israel out of Egypt. The Jerusalem believers were likewise a called-out assembly separated from Judaizers, yet he maintains they were not yet the Body of Christ. In Acts, the Ephesus riot is another example: a mob rushed into the theater because of Paul's work among pagan people, and that gathering was also called an Ekklesia. The King James translators used 'assembly' there, not 'church.' Les says the assembly was being addressed, and we are warned that the Roman authorities were going to call them into question; therefore we must be careful how such terminology either confuses us or sets us straight. Paul also says he persecuted the Church, which Les prefers to call the assembly.