Out 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 TillichEvery person, every place and every action is qualified by this association with the unconditional; it penetrates every moment of daily life and sanctifies it: "The Universe is God's sanctuary. Every work day is a day of the Lord, every supper is a Lord's supper, every work a fulfillment of the divine task, every joy a joy in God. In all preliminary concerns, ultimate concern is present, consecrating them."
Paul TillichThe awareness of the ambiguity of one's highest achievements, as well as one's deepest failures is a definite symptom of maturity.
Paul Tillich