How this union of the soul with God comes about, Jesus does not directly say, but there are many hints in his teaching that bear upon it. “The Kingdom of Heaven cometh not with observation,” he said (Luke 17:20). Religious truth is not reached by “quick turns of self-applauding intellect,” nor by demonstrations. It comes another way. The quiet familiarity with the deep true things of life, till on a sudden they are transfigured in the light of God, and truth is a new and glowing thing, independent of arguments and the strange evidence of thaumaturgy—this is the normal way; and Jesus holds by it. The great people, men of law and learning, want more; they want something to substantiate God’s messages from without. If Jesus comes to them with a word from God, can he not prove its authenticity preferably with “a sign from the sky” (Mark 8:11)? For the signs he gives, and the evidence he suggests, are unsatisfactory. “And he sighed deeply in his spirit, and saith, `Why doth this generation seek after a sign? Verily I say unto you, there shall no sign be given unto this generation.’ So he left them and went up into the ship again and went away.” That scene is drawn from life.
But why no sign? In the parallel passage we read: “`The wicked generation and adulterous seeketh a sign, but there shall no sign be given it, but the sign of the prophet Jonah’; so he left them and departed” (Matt. 16:4). The real explanation of this reference to Jonah is given by Luke (11:32), and missed or misdeveloped in Matthew (Matt. 12:40). Nineveh recognized instinctively the inherent truth of Jonah’s message, and repented. Truth is its own evidence—like leaven in the meal, like seed in the field, it does its work, and its life reveals it. God is known that way. When the chief priests demand of Jesus to be told plainly what is his authority (Mark 11:27), he carries the matter a stage further: Was the baptism of John, he asks, from heaven, i.e. from God, or was it of men? Does God make His message clear, does He properly authenticate Himself? And the uneasy weighing of alternatives, summarized by the evangelist, leads to the answer that they could not tell whence it was; and Jesus rejoins that he has nothing to say to them about his authority. He had taken what we might call an easy case—where it was evident that God had spoken; and this was all they made of it—they “could not tell.” It was plain, then, either that these men did not recognize the obvious message of God ("the word of God came upon John,” Luke 3:9,), or that, if they did recognize it, they thought it did not matter. For the insincere and the trivial there is no message from God, no truth of God—how should there be?