Aside from the difference in ascendancy, between Israel and non-Jews, there is a more obvious difference between this world and the next. Only in this world is there a physical existence. We saw in our study of Parshas Chukas , that red represents the physical man. Similarly, hair is a symbol of vanity. Tum'ah, the adulteration of the mind by physical urges, is iconified by the red heifer.
Hair is also a symbol of physicality.
It serves no purpose but esthetic. This is why a married woman covers her hair, and a nazir, who takes a vow of asceticism, lets it grow wild. Esav is called by two names. The Torah holds up Esav before us as the archetype of man controlled by physical urges, and names him by two symbols of those urges. We are introduced to Esav, when, as a young man, he feels enslaved to a need for some red lentil soup.