Rabbi Tarfon Said: "The Day Is Short, The Work Is Much, The Workmen Are Lazy, The Reward Is Great, And The Master Is Pressing."

The Day Is Short

When a person realizes the nature of the task before him - to conduct his entire life in service of G-d, and to do so in a manner of mili dechassidusa, beyond the measure of the law, he will realize that one lifetime (the "day" allotted for these efforts) is brief indeed. Moreover, the work is even greater than can be conceived by our mortal minds.

(Sichos Shabbos Parshas Masei, 5741)