This week's Torah portion is called Tazria (bearing seed) and begins a long section (spanning this and the following parashah) that describes the laws concerning a disease called tzara'at. This disease manifested as spots on the skin of the body, head, beard, clothing, or even on the walls of houses. This exact disease no longer exists today, but as we have often mentioned, the Torah contains timeless teachings that apply to every place and time in human history.
Beyond the causes of these blemishes, our sages explain, based on the verses in this section, how to identify a blemish to determine whether it is a tzara'at or not. And the process begins by seeing the blemish. The Mishnah says (Nega'im 2:5): "A person sees all blemishes, except his own. Rabbi Meir says, nor those of his close relatives.".
The text refers to the stains of tzara'at; however, our sages explain that this teaching also has a much deeper meaning: the stains it refers to are stains on the soul. We all have different "stains" on our souls—inappropriate attitudes, behaviors, inclinations, and emotions that we neither see nor perceive. We do, however, see the stains of others, as long as, according to Rabbi Meir, they are not our relatives, in which case the love and indulgence with which one perceives oneself extends to our loved ones as well.
Now, despite the Mishnah's profound and revealing nature, there's a problem: it seems the Mishnah should say something like, "Be careful and honest when observing your own flaws," or something similar. That is, understanding human nature's tendency to avoid acknowledging one's own shortcomings, the teaching should warn against and encourage impartiality even regarding one's own flaws. And yet, our sages directly say, "Don't dwell on your own faults; observe those of others!""
The idea behind this teaching is this: given man's inherent nature—to avoid seeing his own flaws out of self-respect—it would be cruel for God to demand that man go against his very nature (with which He created him). The Torah only requires of man what he can accomplish according to his abilities and limitations. Therefore, the Mishnah doesn't instruct man to learn to see his own faults, but rather directs him to focus on the faults of others. However, elsewhere, the same Mishnah states (Avot 1:6): "Get yourself a teacher," thus indicating how to deal with one's own shortcomings.
This should not be understood to mean that one should dedicate oneself to criticizing and pointing out the flaws of other people; on the contrary, the emphasis is that one should make sure to consult with someone about one's own flaws, with the aim of erasing them and growing personally.