In the middle of Parshat Tzav, the Torah states (7:20) that if a person eats from the meat of the Korban Shelamim while Tamei, “Venichreta Hanefesh Hahee Meiamecha,” “This person will be cut off from your nation.” This means that that person will receive the punishment of Karet. But what exactly is this punishment?
There are a number of opinions regarding the exact details of Karet. The Talmud Yerushalmi explains that one who is punished with Karet dies before the age of 50. The Talmud Bavli, however, says that the person will die between 50 and 60. The Ramban resolves the conflict by saying that it all depends on how many sins and merits the person has. If he has more sins than merits, he will live in this world, but will not live in Olam Habah. However, if one’s merits outweigh his sins, he will not live as long in this world, but will live in Olam Habah. Rashi similarly explains that the person will die young. However, he also mentions another important facet of Karet: not only will the sinner himself die, but his children, too, will die prematurely.
I would like to support Rashi with an insight that Rabbi Adler said regarding Mamzerim. A Mamzer is a person whose parents conceived him through forbidden relations, a terrible sin. Because of this, the Mamzer may not marry anyone in Israel except a Mamzeret (a female Mamzer) or a convert. This raises a very troubling question: why would the Mamzer get such a horrific punishment for something he did not even do? It is certainly not his fault that his parents committed the sin of prohibited relations! Rabbi Adler answered that when two people get together, they have such a strong bond that they might easily be willing to suffer a severe punishment for committing such a sin. But if the Torah says that not only they, but also their child, will be punished for their act, they will think twice – parents would never want their child to be so miserable because of what they did. Therefore, there is a punishment for the Mamzer himself.
We can also apply this logic to Rashi’s explanation of Karet. The punishment seems quite logical, because if one’s children are going to suffer for his sin, he might think twice before eating the meat of the Korban Shelamim when Tamei. He would not want his children to die young and not enjoy the pleasures of life for an act that he committed. Thus, according to Rashi, Karet will cause everyone to be cautious before transgressing Karet-deserving act because of the extremely severe consequences.