When it comes to church, there is often a very understandable desire to try to get underneath the programmes and activities to discover what the church really is in itself. If we stripped out all of the busy-ness, what would be the essence that remained? I suspect that very often this sort of thinking comes from people who are weary of the constant round of rotas and commitments that is generally implied by membership of an active evangelical church. In so far as it offers a corrective to our tendency to make church all about bustling around - to Martha rather than to Mary - this desire is very helpful. Nevertheless, it contains within it a potentially serious error about what church is.
Technically speaking, this is a conversation about ontology - what 'being' is, and what it means to exist. In classical thinking, ontology was often conceived of in static terms; behind the activity, and perhaps even behind the particular properties, of a thing or person was the essence, the thing or person itself. Those who take the position outlined above are, probably unwittingly, subscribing to this view.
The desire to just 'be church', without all the activity, is entirely understandable. But it is neither practical nor helpful. Churches do not 'exist', in the sense of having an essence which can be defined apart from their activities.
More broadly, neither does anything else. Continental philosophy after Heidegger has helpfully pointed out that the classical tradition is wrong, at least in so far as it has regard to persons. Persons do not simply exist; they exist themselves in particular ways, in choices and actions, and cannot be abstracted from these choices and actions.
The church cannot simply 'be'- a local church cannot simply 'be' - because the church is not at all a natural association of people. It is born of two (divine) actions, and continues to exist in two (human) activities. God calls the church together, and God sends the church out; the church comes together, and the church goes out. A church at rest is not a church. It has ceased to hear the call of God, and has lost the sense that it comes together at his command; it has ceased to obey the sending of God, and has lost the sense that it must go. Whatever we might call the group of people who continue to assemble, it is not a church. It is an arbitrary assembly, born of human will, and not obedience. The church is defined by action. "Verbs are the circulatory system of the church" (Eugene Peterson)
Whenever a church gathers, if it is a true church gathered in obedience, it is at the centre of a two-stroke movement. People have been called together; when the meeting is over, they will be sent out. The call to worship and the dismissal that bookend the church gathering are echoes of the essential movements of the church. The gathering to worship is the centre, the taking of breath between the coming and the going which must always characterise church.