Eyes, as we all know, are the window to the soul. The Vegetable Root Discourses (菜根譚) takes the metaphor even further:

口乃心之門　守口不密　洩盡眞機　意乃心之足　防意不嚴　走盡邪蹊

"The mouth is the front door of the soul. If you do not guard your mouth closely, your true thoughts [which are supposed to be secret] will all escape. Thoughts are the legs of the soul. If you do not control your thoughts strictly, they will take you down some dark alley."

Why stop there?

• The scalp is the chimney of the soul: as the fire dies down inside, less and less comes out.
• The beard is the front lawn of the soul: if you don't keep it trimmed, your wife will get mad and the neighbors will assume you're a terrorist.
• And James Brown is the godfather of the soul. Just because.