‘But Abraham believed …’

Had Abraham not had faith, then Sarah would surely have died of sorrow, and Abraham, dull with grief, instead of understanding the fulfillment, would have smiled at it as at a youthful dream. But Abraham believed, and therefore, he was young; for he who always hopes for the best becomes old, deceived by life, and he who is always prepared for the worst becomes old prematurely; but he who has faith retains eternal youth.

— Soren Kierkegaard, Fear and Trembling