What Does The Mezuzah Tell You?

The Jew  is unlike all the nations of hte world; he has something to do at all times. The mezuzah is like the yeshiva mashgiach asking the boys going out the door, "Where are yoiu going?" 

​The mezuzah is asking us, "Where are you going?" You have to be mindful of your function as a student of Torah because you are one of the members of the mamleches kohanim, the nations of priests. -- Preface to Shabbos (#439)