“The community that confesses Jesus is Lord has been, from the beginning, a movement launched into the public life of mankind. The Greco-Roman world in which the New Testament was written was full of societies offering to those who wished to join a way of personal salvation. There were several commonly used Greek words for such societies. At no time did the church use any of these names for itself … it used with almost total consistency the name ecclesia – the ecclesia theou, the assembly called by God … The Church could have escaped persecution by the Roman Empire if it had been content to be treated as a cultus privatus.”

— Leslie Newbigin, The Open Secret: An Introduction to the Theology of Mission (Downers Grove, IL: Eerdmans, 1995), 16.