“Faith comes by hearing, and hearing by the word of God.”
What does this mean, you might ask. It means that Christian faith, a firm belief in something not absolutely provable, originates by divine revelation. It is something revealed, something given by God — not as something derived from logic and reason, but as the revelation that is the foundation from which Christians derive all logic and reason. Theology then is, as Anselm said, “faith seeking understanding.” It is not reason deriving truth, but reason derived from truth and explaining truth.
I think, too often, we have forgotten what it means to have faith. The word of God, which is (or should be) the foundation of all Christian thought and practice, is revelation. It is not something that could have been found by people if we merely think. It is not something discoverable by science, because it lies outside the explanatory realm of science. It is, therefore, not a practical knowledge that explains how the world works. Rather, it is a metaphysical answer to why the world exists.