Purim is a holiday of costumes, putting on masks, and presenting ourselves to the world in unusual ways.  It makes sense, then, that this holiday most often falls, as it does this year, in the week after Parashat Tetzaveh, a parashah largely about the costuming for the priests in the Temple.  The fact that the Torah tells us so much about the garments the kohanim must wear cuts against an all-too-common tendency to treat the external as shallow and meaningless.  To the contrary, there is spiritual significance to the garb we wear and the image we present to the outside world.