Barth on Word and Witness: A Three Sentence Summary

I have a confession to make: I've only read one book by Barth and I read it in German, which means that not only have I pulled out a single thread from what looks to be a complex tapestry, I've read it in a language which even Germans find hard to understand.

This circumstance notwithstanding, I offer my attempt at a summary of Barth's understanding of the role of Gospel and Witness in theological study. Please, do tell me how shallow and wrong this is and tell me where to look for a better summary of these issues.

So, here it is:

The goal of theological inquiry is the Gospel of God, a reality distinguishable from yet mediated through the canonical scriptures, understood to be the deposit of the historical witnesses of the prophets and the apostles to this reality in their own time. This reality is one, yet the witnesses are many. As such, the theologian, who can only stand in humble obedience to the superior testimony of the prophets and apostles, must constantly analyse and compare these manifold testimonies in relationship to their common referent, the object of theological science, the Gospel.