"Faith, in the sense in which I am here using the word, is the art of holding on to things your reason has once accepted, in spite of your changing moods. For moods will change, whatever view your reason takes. I know that by experience. Now that I am a Christian I do have moods in which Christianity looks very improbably; but when I was an atheist I had moods in which Christianity looked terribly probable. This rebellion of your moods against your real self is going to come anyway. That is why Faith is such a necessary virtue: unless you teach your moods "where they get off," you can never be either a sound Christian or even a sound atheist, but just a creature dithering to and fro, with its beliefs really dependent on the weather and the state of its digestion. Consequently one must train the habit of Faith."

From Mere Christianity, p. 138-139.

The existence of faith in the Christian life is thus theologically and biblically acknowledged in the never-ending re-visitation of knowledge, assent, and trust.

Faith is a noun: a list of truths believed. Then faith is a very: acting out what you believe. That aspect of faith, to me, is always changing and refining as I grow in understanding and confidence in the noun-type Faith.