Trying to describe ‘The Church’ is an important task for the people of God to engage; and to help us do that I am enlisting Rex Koivisto, he says of the Church:
As we turn to the New Testament (the first place the term is used in its typical sense of Christians), we find several dimensions regarding the nature of the church. The earliest allusion to the use of the term is in fact connected to people: Jesus responds to Peter’s confession and says”you are Peter and on this rock [alluding to Peter] I will build my church [=community of people]” (Matt. 16:18). Jesus was establishing for Himself one great messianic community. The emphasis is primarily on Peter as a prototype of the personal confessor of faith in Jesus and His messianic claims. As such, the idea is that the church is primarily a people, not a structure or organization. (Rex Koivisto, “One Lord, One Faith,” 25)
In this account, the churches’ esse (“essence”) is constituted by the life of God in Christ and the Spirit, and all those, as Peter, who confess ‘faith in Jesus’. This implies that any attempt to describe the church as constituted by ‘this confession of faith’ and a particular episcopal expression, as the “particular expression” of the Church, is in error. The unifying ecclesial core is limited only to Peter’s confession, not to a subsequent episcopal organizational schema that reflects, only one among many, ecclesial expressions of the people of God throughout the various tongues, nations, and tribes of salvation history.
***For an excellent post on the ‘Free Church Tradition’ see an article by Halden***