If God stops a man on the road, and calls him with a revelation and sends him armed with divine authority among men, they say to him; from whom dost thou come? He answers: from God. But now God cannot help his messenger physically like a king, who gives him soldiers or policemen, or his ring or his signature, which is known to all; in short, God cannot help men by providing them with physical certainty that an Apostle is an Apostle-which would, moreover, be nonsense. Even miracles, if the Apostle has that gift, give no physical certainty; for the miracle is the object of faith.
— SØREN KIERKEGAARD