From George Hunsinger’s 1980 essay, “Karl Barth and the Politics of Protestant Sectarianism” (emphasis added):
There is an important sense for Barth in which the church is not to be seen as more sanctified than the world, nor the world as less sanctified than the church. The church shares with the world a solidarity in both sin and grace. This inclusive solidarity meant that Barth found what the church had in common with the world to be always more fundamental than any polarity which might arise on the basis of the church’s human response to Jesus Christ.
Or, as Hunsinger quotes it in Barth’s own words:
[The church] manifests a remarkable conformity to the world if concern for its purity and reputation forbid it to compromise itself with it. . . . As distinct from all other circles and groups, the community of Jesus Christ cannot possibly allow itself to exist in this pharisaical conformity to the world. Coming from the table of the Lord, it cannot fail to follow his example and to sit down at the table with the rest, with all sinners.