The Kohen shall don his fitted linen tunic, and he shall don linen breeches on his flesh.
Linen grows from the ground in individual stalks, similar to human hair.
Rabbeinu Bachya explains that the individualistic nature of each grain signifies the concept of achdus, unity. They reflect an inner harmony, a unified essence. As the grandson of Aharon, the Kohen serves as the paradigm of unity. He reached out to his fellow man to generate inner peace by bringing him closer to Torah. He cites the first pasuk in Sefer Devarim, in which the Torah refers to the geographical location at which Moshe rebuked Klal Yisrael.