Again, a closer look at the historical context of the New Testament will usually reveal that Christianity was NOT a private religious movement. It was accused from the beginning of being in opposition to the secular rulers and world system (and it is!).
Philippi…[was made a full colony of Rome] – the highest privilege obtainable by a provincial municipality. Since their city had this status, Philippians could purchase property and were exempt from certain taxes. When he was in the city, Paul got a glimpse of the Philippians’ pride in their standing as a Roman colony. Paul and Silas exorcised a girl who was being used as a fortune-teller, and as a result her owners became enraged and brought Paul before the magistrates. Their charges are revealing: Paul and Silas, they said, were “throwing our city into confusion” by encouraging “customs (ethe) which it is not lawful for us to accept or to observe, being Romans” (Acts 17:1-9), the apostles were seen as subversives, both of the POLIS and the empire.
And further on:
Paul’s claim that Christians are citizens of a heavenly politeuma [greek – state/commonwealth of citizens] further indicates that the Philippian Christians are to consider themselves a colony of heaven more than as a colony of Rome. Paul imitated Christ by giving up his privileges as Hebrew of the Hebrews, and he exhorted the Philippians to follow his example by treating their Roman citizenship and attachment to the Roman emperor as “rubbish” for the sake of Christ and His heavenly politeuma.
In short: throughout Philippians, which some identify as one of the least political of Paul’s letters, Paul was treating the Church as an alternative to the politico-religious oranization of the city and of the empire.
-Peter Leithart, Against Christianity, Ch.1 Sec.11