Faith is realizing not all truth is within your power to apprehend, by definition. It's first coming to terms with the existence of unknown unknowns. In the case of the Christian faith, it's understanding that it's impossible for a these unknowns to become known by definition (in the sense of fully understood) — and yet necessary to their definition (only a good, personal God can create people with any good in them) that they be made known (in the sense of revealed, apprehensible). This leads to hope — the idea that our souls might be fundamentally transformed to enter more fully into the mystery of the known (revealed) unknown.