This from Robert Browning (everyone knows the first part):
If a man’s reach does not exceed his grasp, what is heaven for?
Browning was teaching a class one day and a woman raised her hand. “Professor Browning,” she said. “I love your poetry and I have read all your poems. There is one line, however, I just don’t understand.” She quoted the line. “Can you tell me what you meant?”
Browning considered the question for a moment. Then he said, “You know, when I wrote that line only God and I knew what it meant.” He paused, then continued, “Now only God knows.”