Judaism teaches that everything has the potential for holiness; after all everything in this world was created by G-d. But it is up to man to actualize that potential and imbue the world with holiness. Eating, marital relations, and earning a livelihood are not only a means to an end, but if done properly are acts that are instinctively holy and the fulfilment of a divine mitzvah. The physical and spiritual worlds are not meant to be in conflict but rather are meant to complement each other.
Our Sages teach us that "one hour in this world filled with mitzvot and good deeds is better than all of the world to come" (Avot 4:17). It is only in our physical world that mitzvot have any meaning. One can not perform mitzvot in the world to come, a world devoid of physicality. Mitzvot is the link that brings the physical and spiritual together. Similarly, sinning creates a dissonance between the physical and spiritual. Hence it should come as no surprise that our Sages teach that spiritual ailments can have physical manifestations.
The Torah goes into great detail describing the laws of tzara'at, its diagnosis and treatment. Yet it is difficult to imagine that the main concern of the Torah was treatment of a physical disease. If so, one would call upon a doctor to examine its manifestations, not a kohen as called for in the Torah. It is clear that preventive medicine is not the issue.
The Torah tells us that a metzora is to be separated from the community, yet our tradition tells us that no one would be declared a metzora and hence separated from the community before Yom Tov, the time when masses of people gathered in Jerusalem. Clearly the Torah was concerned not with the medical ramifications of tzara’at but rather its spiritual ones.
"And the tzarua on whom the plague is, his clothes shall be rent, his head shall be unkempt, and he must cover his head down to his lips and 'impure, impure' he must call out" (Vayikra 13:45). The Kli Yakar sees here an allusion to the three sins which are at the root of tzara'at; gossip, arrogance, and excessive materialism. The Torah therefore prescribes that the metzora must tear his garments to atone for one's focus on material possessions. Furthermore, the Torah declares that even one's home can be "infected" with tzara'at and may need to be destroyed. More important than our physical house are the Torah values that emanate from our home. The hair of the metzora must be unkempt symbolizing that he who thinks he is greater than others, that he is the top, shall have his top frazzled. And the covering of the lips symbolizes that the best form of teshuva is to refrain from talking about others. That way lashon hara and all of its appurtenances can be avoided.
It is worth noting that it was only after the sin of the Garden of Eden that man begins to wear clothes. A close reading of the Biblical text reveals that G-d's anger with Adam for eating from the tree of knowledge stemmed from Adam's speaking lashon hara against his wife, blaming her for his own failing. Tearing our clothes remind us of that "original sin" of speech, a sin that caused the physical and spiritual worlds to be in conflict [1].
Man is prone to both physical and spiritual diseases. The tragedy is when the symptoms of disease come too late and we walk around thinking we are healthy when we are truly sick. When a physical disease is not caught in time tragedy results. While it is always best to nip spiritual diseases in the bud, it is never too late to affect a cure. Teshuva is always therapeutic; not only does it cure us spiritually, but it can literally make us feel better physically. The malaise that we often feel with life can often be alleviated when our moral convictions are strong and have been integrated into all aspects of our lives.
[1] A mourner rips their clothes symbolizing that with departure of the physical body man goes back to his state of purity where clothes were not needed.