Faith as the state of being ultimately concerned implies love, namely, the desire and urge toward the reunion of the seperated.
Paul TillichOut of the element of participation follows the certainty of faith; out of the element of separation follows the doubt in faith. And each is essential for the nature of faith. Sometimes certainty conquers doubt, but it cannot eliminate doubt. The conquered of today may become the conqueror of tomorrow. Sometimes doubt conquers faith, but it still contains faith. Otherwise it would be indifference.
Paul TillichCulture (science) is the form of religion; Religion is the substance of culture (science).
Paul Tillich