“The true growth which is the secret of the upbuilding of the community is not extensive but intensive; its vertical growth in height and depth. If things are well—and there is no reason why they should not be—this is the basis. The numerical increase of the community indicates that it is also engaged in this very different increase. But the relationship cannot be reversed. It is not the case that its intensive increase necessarily involves an extensive. We cannot, therefore, strive for vertical renewal merely to produce greater horizontal extension and a wider audience. At some point and in some way, where it is really engaged in vertical renewal, it will always experience the arising of new Christians and therefore an increase in its constituency, but perhaps at a very different point and in a very different manner and compass from that expected. If it is used only as a means for extensive renewal, the internal will at once lose its meaning and power. It can be fulfilled only for its own sake, and then—unplanned and unarranged—it will bear its own fruits. As the communion of saints takes place, the dominant and effective force is always primarily and properly that of intensive, vertical and spiritual growth.”
- Karl Barth, Church Dogmatics 4.2, 648.