Dietrich Bonhoeffer's liberal use of spatial concepts in constructing an ecclesiology served his theological purpose in the articulation of a concrete ecclesiology. In particular, Bonhoeffer uses the themes of taking-up-space and the visibility of the church. The visibility of the church is depicted as a proclamatory space, a liturgical space and an ordered space, all encapsulated in the concept of Lebensraum. Within this space, witness is given to the foundation of all reality in Jesus Christ. The church is the place where this reality is proclaimed; a space no bigger than that required to serve the world in witness to Christ. As opposed to any idea of a ‘privatised’ or individual space, Bonhoeffer insisted on the public and territorial nature of this space as essential to the church's witness, for it was in this very visibility that the church gains space for Christ.
Lebensraum, an idea popularised by Adolf Hitler and incorporated into the foreign policy of the Third Reich, was a highly charged political concept taken over by Bonhoeffer to represent a living space diametrically opposed in form to that proposed by the Reich. A useful way of thinking about the Christian form of Lebensraum as proposed by Bonhoeffer is to regard it as the space in which the ‘social acts that constitute the community of love and that disclose in more detail the structure and nature of the Christian church’1 are to be demonstrated and observed. These ‘social acts’ are built upon the foundational concepts, first found in Sanctorum Communio, of Stellvertretung or vicarious representative action, Miteinander or church members being with-each-other, and Füreinander or church members actively being for-each-other. Bonhoeffer proposes that, as its life is lived out in this way, the church will take the form of its suffering servant Lord. It is in this particular space and no other, grounded and upright in Christ, that Christians are to live their lives in witness to Christ.