I once heard the story of ten medical students that went forth to their biochemistry class. And five of them were wise and five were foolish. They that were foolish, took their cell phones and laptops, but failed to bring their pencils, erasers, and calculators. But, the wise always took their pencils, erasers, and calculators with them. While the class proceeded, they all listened attentively. And, during the middle of the class was a cry made, "Behold, the professor cometh with a surprise exam!" Then all of the students arose, and got ready their material. And the foolish said unto the wise, "Give us your pencils; for we have none of our own." But the wise answered, saying, "Not so! Lest there be not enough for us and you: but go rather to them that sell, and buy for yourselves." And while they went to buy, the exam commenced and the professor shut the door. Afterward came also the foolish students saying, "Professor, open the door to us." But he answered and said unto them, "I know you not."