Do you love the church for what it could be or what it is? If the former, I suggest you read Dietrich Bonhoeffer’s magisterial little book, Life Together. It is, so I think, his best book. No need, however, to debate what is neither provable nor non-falsifiable — what one thinks is his best book another will not.

What is worth discussing is his incredible set of statements about the expectations we bring to the church and that we expect of the church and how our expectations, when they encounter the realities, are dashed to the ground.

What is worth discussing is that until we realize that the eucharist table is at the front of the church under the cross — because those who come into the fellowship and “cracked Eikons” and in need of grace and healing — we will not comprehend what the church is.

Leaving the church because it does not meet our expectations is failing to understand what a church is; we have a church because we have failed to meet God’s expectations. Failed expectations, then, are the foundation of the church and the reason for its existence.

Leaving the church because it does not meet our expectations is to create a church for ourselves. It is, if I may be so bold, idolatry.

Many enter into ministry with the ambition to make a church what they think it could be instead of what it is.

Until we understand what the church is — a fellowship of sinners at different locations in a journey — we will not understand what the church could be and can be. No two Christians are perfectly compatible — in theology or praxis — and therefore there will be tension in the church, which is precisely where we need to begin to see what the church is. Not a fellowship of those who agree or who are alike but a fellowship of those who don’t agree and who are not alike. When we demand the church be like us, or like our vision for what it is, or we leave, we create our own church — and eventually, if we have the guts, we start a church that begins the same old process of a fellowship of those agree who eventually become those  who disagree and who split. Bonhoeffer still speaks.

In my classes at Northern Seminary in Chicago, I routinely allude to Life Together.  Here are my favorite lines, lines that follow on from his important claim that Christian fellowship is “through” and “in” Jesus Christ:

This dismisses at the outset every unhappy desire for something more. Those who want more than what Christ has established between us do not want Christian community. They are looking for some extraordinary experiences of community. … Such people are bringing confused and tainted desires into the Christian community. Precisely at this point Christian community is most often threatened from the very outset by the greatest danger … the danger of confusing Christian community with some wishful image of pious community, the danger of blending the devout heart’s natural desire for community with the spiritual reality of Christian community.

Now hear this:

Only that community which enters into the experience of this great disillusionment with all its unpleasant and evil appearances begins to be what it is should be in God’s sight, begins to grasp in faith the promise that is given to it.

And this:

Those who love their dream of a Christian community more than the Christian community itself become destroyers of that Christian community even though their personal intentions may be ever so honest, earnest, and sacrificial.

Those who dream of this idealized community demand that it be fulfilled by God, by others, and by themselves.

Scot McKnight is author of The Jesus Creed. He blogs at Patheos.com, where this post originally appeared.