There are three types of tzaraas that can afflict the Jew, as a reminder from G-d that he is not living correctly. At first, the tzaraas attaches itself to the sinner's house, then to his clothing, and finally, if he does not repent, it adheres to his very flesh. His body bears the signs of this spiritual illness, and the cure, so to speak, is also spiritual - teshuva (repentance). The metzora does not go to a doctor, but to the kohen. When he is ready for purification, he does not go to a medical clinic but to the Beis HaMikdash. Why are these particular three entities the targets of this affliction - his home, clothing, and body? And why this progression? Why not just attack his body immediately? Why the subtlety?
Chazal says (Arachin 16a) that tzaraas is visited on a person for one of seven possible sins, most famously Lashon hara, but also for others, such as arrogance, envy, etc. What is the connection between arrogance and tzaraas?
We do many things to generate self-importance, sometimes to inflate our egos but more often simply to raise our self-esteem. We endow the most mundane acts with glamour, prestige, and a certain cachet. These days, people gladly pay ten times more for a cup of coffee than they did just a decade ago, only because it engenders a sense a sophistication and a feeling of trendiness. We tend to invest the simplest acts with the most profound significance.

In and of itself, this is usually harmless; the real danger lies in doing the same thing in our interactions with others. Lashon hara is a by-product of arrogance. One who thinks he is superior to others, or one who wants to boost himself, will often seek to degrade others. People who are emotionally secure do not need that, but those who are most self-centered thrive on it. So what is the first punishment of the Metzora? He is quarantined, banished from society for seven days - in essence, humbled, diminished, and losing esteem in the eyes of others. The metzora is segregated not only as a punishment, but primarily as a learning experience - so he can reflect on what it means to be part of a society, on the value of human companionship, so he can better appreciate human companionship - because therein lies his flaw.

The metzora has no respect for the rights, needs, or claims of others. He lives in a world in which he is at the center, the hub of importance, and the straw that stirs the drink. In other words, he is not only arrogant, but also worse - he is rude. To be rude doesn't violate one of the 613 commandments; it violates all of them. In our world, we have become inured to the death of civility, so we accept rudeness as a matter of course and we almost pay it no attention, until it affects us. The etiquette of "please, thank you, excuse me, sorry" is in decline in our world.

But G-d will not first punish the person. In His kindness, He will first target those objects with which the Metzora identifies, which bring him security, and add to his sense of self: first his house and then his clothing.

People invest much in their homes - money, time, effort, personality, and aggravation. It is a very keen expression of their identity. It is 'who I am' to the outside world. We all have homes, and yet no two homes are alike. And clothing is an even more immediate and trenchant means of self-expression - there are rules and regulations (what matches or doesn't, what is in and what is out of fashion), infinite styles, and endless supply of compliments. ("That's a beautiful suit/dress, etc." - even though the recipient of the compliment did not make the garment, he\she is just wearing it.) And yet, nothing is closer to us than our bodies, where we feel pain, and which is most important to us.

These three are familiar to us in another context as well. Gemara Menachos 43b states that "whoever has tefilin on his head and arm, and tzitzis on his clothing, and a mezuza on his doorpost is secured against sin.." These three items, explained Rav Yisrael Chait shlit"a - are our primary means of self-expression, the focal points of our individual identity and putative security. These are the areas of life that G-d specifically endowed with mitzvos, in order to re-direct our trust back to Him.

If we think that our homes are our castles and furnish us with security and strength, then we are commanded to put a mezuza on the outside door - to remind us that the true refuge is with G-d. If we are obsessed with our appearance - how we look, what we wear, on maintaining the latest fashions, then we are provided with one sartorial constant: Tzitzis. For those who think that man exists only to seek pleasure and indulge the body, know - through the wearing of tefilin - that the body can be consecrated to a higher purpose. Man is first and foremost a servant of G-d.

The metzora, in his arrogance, stumbled. He is first taught - through his home, then through his clothing, and then on his body - to gain some perspective, regain some humility, to re-create himself as a wiser, more dedicated servant of HaShem. But what the metzora learns through an affliction, we understand through mitzvos. That is why tzaraas only affects Jews, and mitzvos were only given to Jews - and that is why we remind ourselves, in this month of geula, of the foundation of our people, the terms of our existence, and the glorious destiny that awaits His faithful servants, with the joys of redemption, and the coming of Moshiach.