What is Lashon Hara? - Based on Torah by Rabbi Elimelech Biderman, shlit"a

The Severity of Lashon Hara
The Gemara (Shabbos 155:) לית דעניא מכלבא ולית דעתיר מחזירא "Nothing is poorer than a dog and nothing is wealthier than a pig.” Rashi explains, a pig is wealthy because, "It can eat all types of food, it finds food on its own, and people tend to feed it." A dog is poor, as Rashi explains, "No one has compassion on a dog to give it a lot of food." Why is this written in the Gemara? Why do we need to know that a chazir (pig) is wealthy and a dog is poor? The Vilna Gaon zt'l explains that the wealthy pig signifies the prohibition of eating chazir. The poor dog represents the aveirah of speaking lashon hara. (As the Gemara [Peschaim 118.] says, “Whoever speaks lashon hara…it would be proper to throw him to the dogs.”) The chazir is very wealthy. This means this prohibition is very well kept. There isn't another sin in the Torah that is upheld as scrupulously as this one. Even many nonreligious Yidden refrain from eating chazir. In contrast, people are, unfortunately, not very careful with lashon hara. It’s the poorest sin, as it is so neglected.
Every mitzvah has its mazal. The prohibition of eating chazir has a very good mazal, while lashon hara has a bad mazal. It isn't because the aveirah of lashon hara isn't severe. The Gemara compares lashon hara to the three cardinal sins: ע״ז,גילוי עריות, ושפיכות דמים idol worship, murder, and adultery. And the Or Hachaim HaKadosh (14:9) writes, “Nothing distances a person from his Creator like lashon hara.” Lashon hara also causes a lot of suffering in this world. Rashi (14:4) writes, לפי שהנגעים באים על לשון הרע Tzaraas, "comes from speaking lashon hara…" There is no more tzaraas in these days. But the punishments of tzaraas continues in other forms.
As the Chofetz Chaim (Shemiras HaLashon, Zechirah ch.6, 8) teaches: "The Tikunei Zohar writes that this severe sin [of lashon hara] causes poverty, chas veshalom. Therefore, someone who desires to live well should be cautious about speaking lashon hara… I also saw in holy sefarim that when one speaks lashon hara, he has less food to eat, like the snake, who was cursed, and has less to eat. It is obvious that if a person speaks lashon hara constantly, his punishments of poverty and tzaros will also be constant… It isn't solely they who are punished. The entire world is punished because of them. There will be a lack of food for the entire world. As the Gemara (Taanis 7) states, 'Rains stop because of those who speak lashon hara…' Speaking lashon hara also causes wars and death in the world, as the Zohar tells. Therefore, someone who cares about his life, and about the wellbeing of the world, should be cautious with his speech. It will be good for him in this world and in the next world."
So, we see that although one won't get tzaraas today for speaking lashon hara, poverty and suffering do make their appearance. That is how tzaraas appears in our times. He will also have tzaraas on his neshamah (soul). This form of tzaraas applies to all generations. It states (14:35), כנגע נראה לי בבית "I saw something that appears like tzaraas…" Rashi explains, "Even a Torah scholar who is certain that he has tzaraas shouldn’t tell [the cohen] with a certainty that he saw tzaraas. He should say like appears It, 'כנגע נראה לי tzaraas.'" Why can't he say, "I saw tzaraas"? Reb Chaim Vital zt'l explains that the primary tzaraas is on the neshamah. Therefore, one says, כנגע נראה לי בבית " I saw something that appears like tzaraas,” but it isn’t the primary tzaraas. The primary tzaraas is on the neshamah. It is also common sense that one should avoid speaking lashon hara. If one traces the origin of all disputes, he will find that negligence with the laws of lashon hara stands at the root. The Dubno Magid expresses this point with a mashal (parable): Someone once came to his doctor and complained of chest pains. The doctor spoke to him about the importance of being cautious about getting angry. The patient interrupted the doctor, "If I wanted to listen to a mussar drashah, I would have gone to the beis medresh. I came here to hear medical advice..." The doctor said, "You don’t understand. I'm giving you medical advice. I’m explaining to you that for your health, you must be cautious with your anger. If you become angry, you will suffer chest pains, which could lead to a heart attack…" Similarly, guarding one's speech isn't good only for spiritual reasons. It is good in this world, too. It saves a person from a lot of trouble. As a wise man said, "Before I speak, I rule over my words. After I speak, the words rule over me."
The Beis HaLevi zt'l would often open his tabak pushkeh (snuffbox), look inside, and then immediately close it. One of his students was curious about that practice, so when the opportunity arose he opened the snuffbox and found the written שפ״ו שמ״נ letters inside. He asked the Beis HaLevi about it. The Beis HaLevi told him that they are roshei teivos (acronym) ,שומר פיו ולשונו שומר מצרות נפשו for "Someone who guards his tongue protects himself from troubles." The Midrash (Metzora) teaches: There was once a peddler who wandered from town to town and would announce in the marketplaces מאן בעי סמא דחייא "Who wants the elixir for life?" Reb Yanai told the peddler he wants to buy that medicine. The peddler replied, "People like you don’t need it." When Reb Yanai insisted that he wants to buy it, the peddler opened a Tehillim and read (Tehillim 34) מי האיש החפץ חיים... נצור לשונך מרע, "Who is the person who desires life…? He should guard his tongue from speaking bad." Reb Yanai said, "I’ve been saying this pasuk (verse) my entire life and I never knew its meaning until that peddler explained it to me!” What did Reb Yanai learn from this peddler that he didn’t know before? The Dubno Magid zt'l explains that Reb Yanai originally thought the pasuk was saying that the reward for cautious speech is longevity. The peddler taught Reb Yanai that long life isn't a reward. Rather, it is a natural effect. When one is cautious with his speech, he will avoid disputes and many hardships, and thereby he will live a long life. After learning all the above, we can understand the severity of lashon hara. Yet people are still negligent with this prohibition. As we explained, it is the poorest mitzvah. But those who are cautious will earn immense benefits in this world and in the next.
Why People Speak Lashon Hara
It states (Koheles 10:11), אם ישוך הנחש בלא לחש ואין יתרון לבעל הלשון, "A snake bites…and there is no gain for the person who speaks lashon hara." The Gemara (Taanis 8.) explains, "In the future, all animals will go to the snake and ask him, 'A lion pounces and eats, a wolf attacks and eats, but what benefit do you gain from biting [and poisoning people]?' "The snake will reply, 'And what benefit does a person who speaks lashon hara gain?'" There is no pleasure in speaking lashon hara. There is no gain. So why do people speak it? The Pele Yoetz (Kinah) says that it is caused by jealousy. He writes, "A person's heart is bad. He wants to be the only person who has wisdom, does good deeds, owns wealth, receives honor, etc. And therefore, he is upset when someone else reaches his level, or is greater than him. He is jealous, he wants his [fellow man's] downfall, and he wants to slander him… If a person desires life, he should run away from this attitude. He should be a warrior and conquer his yetzer hara. He can do so by believing with emunah sheleimah (complete faith) that no one can take away from him what is destined for him. Even if he would be the only person in the world, he won't earn more than the amount that was decreed for him. And even if there would be thousands of merchants, all selling the same products as him, it wouldn’t take away from the amount that was destined for him. He should be happy with Hashem's will, Who does what is best for each person."
If the Pele Yoetz wouldn’t have mentioned it, we wouldn’t recognize the connection between jealousy and lashon hara. But now that the Pele Yoetz (and other holy sefarim) teach us that the origin of lashon hara is jealousy, a person can test himself and recognize how true it is. When one is jealous of someone who has wealth or honor that he hoped would be his own, this causes him to be angry with that person and to speak lashon hara about him. The solution is to come to the realization that everyone gets what's destined for him, and no one is taking anything away from you. It states (Metzora 14:9),והיה ביום השביעי יגלח את כל שערו את ראשו ואת זקנו ואת גבות עיניו ואת כל שערו יגלח, "It will be on the seventh day [of the purification of the metzorah], he should shave off all the hair on his head: his beard, his eyebrows, all his hair shall be shorn." The Ben Ish Chai explains this mitzvah based on the following Gemara (Bava Basra 16): “Hashem says, 'I created in man many hairs. Each hair has its own pore, so that two hairs won't draw their nourishment from the same pore. If two hairs grew forth from the same pore, the person would become blind…” When the מצורע shaves his head, he discovers that each hair has its own root. No hair can take away the nourishment that was destined for another hair. He thereby realizes that likewise, no one can take away parnassah (livelihood) that was destined for him. As he cuts his hair, he remembers the Gemara (Yoma 38), "No one can touch what is destined for his friend — not even a hairsbreadth." These ideas help him overcome jealousy. There is no reason to be jealous, because no one is taking anything away from him. By remembering this, he won't be jealous, and he won't speak lashon hara.
The Gemara (Eiruchin 15:) says, "Whoever speaks lashon hara is kofer be'ikar (denies Hashem)." What is the connection between lashon hara and denying Hashem? As we explained, lashon hara comes from jealousy. Jealousy is roused when one doesn’t believe that everything is bashert (destined). Because if he believed that everything is bashert, and no one can take anything away from him, he wouldn’t be angry, jealous, or slander anyone. If he nevertheless speaks lashon hara, this is a sign that he didn’t internalize this truth. He is kofer be'ikar because he lacks the fundamentals of emunah.
A second cause, that brings people to speak lashon hara, is disrespect to others. They look down at people, and therefore they don’t consider it wrong to speak badly about them. It states (13:46), מחוץ ישב בדד מושבו למחנה, "He should sit alone. His place is outside the camp." Reb Zalman Sorotzkin zt'l (Oznayim LaTorah) explains that people speak lashon hara about others when they look down on them and they don’t recognize their importance. The Torah therefore obligates the metzora to sit outside the camp. As he sits there alone, he will need people to bring him food and care for his needs. That's when he will realize how much people are dependent on one another. And with that recognition, he will come to respect his fellow man. He will know that each person is important, as each person brings something to the world that is beneficial for mankind.