Patrick Swayze said it at the end of "Ghost.":
"The love inside, you take it with you."
But it occurred to me this morning. You may not take all your knowledge with you. Perhaps your knowledge dies with you. That's why you must share and spend it, spread it around while you are alive. Knowledge is meant to stay in this world, to make this world better. It does not help the next.
That's why I teach.