A paraphrase of a Chassidic story:
A rebbe noticed that one of his students had his face buried deep in a machzor (a High Holiday prayerbook) and seemed to be ignoring the lesson at hand.
"Moshe," the teacher said, "What are you studying so intensely?"
"I'm sorry, rebbe," the student replied, "But the High Holidays are approaching and I must review the machzor to be sure that I am prepared."
"The mavhzor has not changed since last year. You have. You would be better served if you studied yourself."