Church Dogmatics 4.1, 371-2:
It must be noted that the voice which we have heard is not that of 18th century rationalism but 17th century orthodoxy. This theology had not been taught by the Reformers themselves to learn from Jesus Christ as the substance and centre of Scripture what is the will and Law of God and therefore what the sin of man is. And the theology itself obviously had no power of itself to rectify the omission. For this reason it could and indeed had to think with a growing intensity and speak with an increasing clarity along the lines discussed. At this critical point in its exposition of revelation – hesitantly at first, but then more confidently – it could and had to go beyond the Scripture principle which it proclaimed so loudly to another principle, that of reason. The transition to the Enlightenment and all that that involved was not the terrible innovation that it has often been called. In many respects, and in this respect also, orthodoxy itself was engaged in a wholehearted transition to the Enlightenment – a further proof that the slogan “Back to Orthodoxy,” and even the slogan “Back to the Reformers,” cannot promise us the help that we need to-day. “Back to …” is never a good slogan.