Karl Barth quotes - page 4
Frederick the Great (1712-1786) once asked his personal physician, Dr. Zimmermann, "Can you name me a single proof of the existence of God?" Zimmermann replied, "Your Majesty, the Jews!" By that he meant that if one wanted to ask for a proof of God, for something visible and tangible, that no one could contest, which is unfolded before the eyes of all men, then we should have to turn to the Jews. Quite simply, there they are to the present day. Hundreds of little nations in the Near East... have dissolved and disappeared in the huge sea of nations; [only] this one tiny nation has maintained itself.... If the question of a proof of God is raised, one need merely point to this simple historical fact. For in the person of the Jew there stands before our eyes the witness of God's covenant with Abraham, Isaac, and Jacob, and in that way with us all. Even one who does not understand Holy Scripture can see this reminder.
Karl Barth