Rabbi Finkelman, in his Purity of Speech adaptation of the Chofetz Chaim’s Sefer Shmirat Halashon, teaches that the immediate physical punishment for speaking lashon hara can be seen as having benefitted the Jews back when this punishment was in effect. Jews who spoke lashon hara were punished with Tzaraat – leprosy. How could being struck with leprosy possibly be a good thing?
Rabbi Finkelman explains that when leprosy was the consequence of speaking lashon hara, Jews were conscious of when they’d misspoken. They knew what counted as lashon hara. Today, you often hear people defend their gossiping by saying that it isn’t lashon hara. People know they should speak kindly about their fellows, but it’s difficult. To avoid feeling bad, they justify their unkind words as something that doesn’t qualify as lashon hara.
In the Bible, Miriam is struck with leprosy for speaking ill of her brother Moses. In the following Parasha, the spies are sent to scout out the land. One well-known way of interpreting the Torah is by considering juxtapositions, things placed alongside each other.
Rashi explains why these two stories, seemingly unrelated, are stuck together. The spies – who were leaders of the 12 tribes of the Children of Israel – should have learned from Miriam’s punishment. They should have seen how dangerous speaking lashon hara is.
Unfortunately, they didn’t learn the lesson. And as a result of their negative report, G’ decided that that generation would not enter the land of Israel, but die in the desert. Thus began 40 years of wandering in the desert. And during that time, the whole generation died. (They’d asked Moses to send spies into Israel.)
When in doubt as to what counts as lashon hara, it’s better to keep quiet. Lashon hara carries serious consequences, even if they’re not as immediately obvious today, as they once were.