The majority of the parshiot of Tazria and Metzora deal with cases of tumah (ritual impurity), where a person becomes ritually impure or tamei. One of the most common examples of this phenomenon is tzara’at (commonly mistranslated as “leprosy”).
Tzara’at is a color disfigurement in one’s skin, clothes or belongings and is caused by someone speaking lashon hara (gossip or slander) about another person. In order to become tahor (ritually pure) one must see a Kohen and go through a one or two week purification process.
Although tzara’at is only one kind of impurity mentioned in these two parshiot, it reflects a general theme throughout each one. Does tzara’at have any physical affects on the body besides a superficial discoloring? No. Will somebody get their hand cut off if these have tzara’at? No. Then what is its purpose? When you get tzara’at, a body part turns color and is “ugly.” What the tzara’at is doing is it’s reflecting how your inner character has suddenly become “ugly.”
A metzora (someone who had tzara’at) is someone who had spoken ill of their fellow human being, exposing an embarrassing action to others. The Torah treats this with a serious regard by ostracizing the slanderer from the community for at least a week. Since the slanderer separated someone else from the community by speaking badly about them, he is expelled from his own group not even being allowed to live with other metzoras. The inner defect is being manifested in a physical setting so the metzora can see that he needs to improve and return the “color” back to his skin, or return the good back to his soul.
If you haven’t noticed, you haven’t seen too many people walking around with yellow spots on their arms these days. The reason why tzara’at doesn’t exist anymore is that the Beit HaMikdash (Temple) no longer exists and along with it many of its procedures are removed, too. But since we no longer get tzara’at, it is up to us to make sure that respect our fellow human beings and not make that snickering remark about them. The laugh you get from that joke will last a few seconds, but the pain they will receive will last for months, if not years. I hope we can take a lesson that if the Torah is taking two portions’ worth of space to discuss that laws of tzara’at and other impure states they might be worthwhile to study.