I have my head full of this stuff at the moment, but this quotation epitomizes for me the reasons why Barth continually resists easy summary and when read closely, why it is best to resist the temptation to call him as a witness for one or other side of contemporary debates about the interpretation of Scripture.
From a human standpoint the preservation of the Church depends, therefore, on the fact that Scripture is read, assimilated, expounded and applied in the Church, that this happens tirelessly and repeatedly, that the whole way of the Church consists in its striving to hear this concrete witness.
So far, so typically Barth, but this comes next:
As a rule the step aside which means a step into the abyss of death, the fatal lack of this self-forgetful attention, will scarcely betray itself as such at once. It will normally take the form of great fidelity (to what the Church has said) and great zeal (for what the Church believes that it must itself say) … Whenever life is exchanged for death, or death for life, in the Church, this fidelity and zeal are usually operative: much good will, much serious piety, wide vision, deep movements, and in it all the sincere conviction of not being in any way self-willed but rather being obedient to the Word of God.
both quotations from CD I/2, 691 (emphasis added)
So, it seems, claims to scriptural fidelity (what the church has always taught) and spiritual zeal (for speaking a word that is relevant) can be the clearest manifestations of an ecclesial refusal of the freedom of the Word of God.