To even make faith a sort of disposition that is required (a feeling, a cognitive awareness, a self-understanding, a longing, a desire) is problematic in that, however minute and simple, however easy, the very fact that it is found in you makes it questionable. "Faith is uncertain," Luther once said, and his diatribes against the same have gone scarcely noticed by theologians today. The matter becomes wholly relative; a sort of gaseous pathogen that flits from one portion of the human construct to another, always escaping the gaze or, if caught, evaporating.
Barth once called faith a pure negation, a pure lack, a vacuum. He was right, and right also to immediately speak against turning this into a human thing. Faith is not a human thing. It is in us, but we cannot locate it or describe it. It is in us, but there is no part of it to which we are attached. We cannot say that we have it, yet a paradox forms in the epiphenomenon of assurance and joy. How can these things come if one does not know faith? Justifying faith! Yet as soon as we return to our self-reflection, the despair returns. Human achievements work despair alone.