The church as the real content of the gospel, its glory the boundless manifestation of the heavenly Lord, sharing in it being identical with sharing in Christ and his dominion, his qualities being communicable to it–we know that message. It has lasted for two thousand years, has fascinated Protestantism, too, and is today the main driving force of the ecumenical movement. If only the theology of the cross were brought in to counterbalance it! But the church triumphant, even if it starts from the cross and guards it as its most precious mystery, has still always stood in a tense relationship to the crucified Lord himself. As long as the tension remained alive in it under violent friction, one could in some degree come to terms with the situation. The greatest danger always arose when the church pushed itself into the foreground so that Christ’s image above it faded into an image of the founder, of the cultic hero, or became an ecclesiastical icon to be put side by side with other icons that were set up from time to time. It was against that danger that the Reformation in fact rose up, not against the secularization of the church, although the two things necessarily went together. Where the world is dominated by the church, and even Christ is integrated in its metaphysical system, the church becomes conversely a religiously transfigured world. Its real Babylonian captivity, however, consists in its making itself the focal point of salvation and the theme of the gospel. The church’s introversion puts it into the sharpest contrast with the crucified Lord who did not seek his own glory and gave himself to the ungodly.
— Ernst Käsemann, Jesus Means Freedom (1969)