Parshas Tzav (6:3) begins with the laws governing the service of the Kohanim in the Mishkan. Rashi writes that the bigdei kehunah [priestly garments] worn by the Kohanim could not be too big or too small and had to be custom-made to their size.
Why did the bigdei kehunah have to be tailor-made to precisely fit each Kohen, and why is this point stressed here in conjunction with the Avodah [Divine Service]?
A popular aphorism says that “clothes make the man,” as our clothing reflects the way we portray ourselves to the world. Rabbi Chaim Zvi Senter explains that if a person wears a garment that is too big for him, he is symbolically presenting himself as larger than he truly is in an attempt to assume a role for which he is not suited. Because a Kohen is in the spotlight while serving in the Mishkan, the Torah cautions him against wearing oversized clothing to pretend to be someone he is not.
On the other hand, a Kohen’s clothing can also not be too small. This requirement teaches that it is equally unacceptable to shirk the responsibilities of leadership by trying to deny one’s position and unique abilities. Only when we have an accurate self-image of who we are and what role we are meant to fill can we be correctly outfitted with the proper wardrobe to serve Hashem, a valuable lesson for Kohanim and non-Kohanim alike. (R’ Ozer Alport)