Indeed, Korach's unusual demise demands an explanation. In most instances, the Israelites who sinned were struck down in a plague. And even in this story, there is an alternative punishment used for other rebels. Moses tells all those who would presume to the priesthood to bring incense to the tabernacle. They do, and at the critical moment, they are consumed in fire. That, at least, is a punishment we have encountered elsewhere. Aaron's own sons, Nadav and Avihu, died in a Divine fire after having brought a sacrifice "that they were not commanded to bring."
Our sages in the Mishna tell us of 10 things that were created in the last hour before that first Sabbath in Genesis. One of them was the "mouth of the earth" which swallowed Korach and his fellow rebels. So we know it was unique, but why was it deserved? Let's take a closer look at his sin.
The rabbis trace the genesis of Korach's rebellion to his being passed over for the presidency of the tribe of Levi. Amram, the father of Moses and Aaron, was the oldest of the four sons of Kehat, one of the three main branches of the Levites. Korach was the son of Yizhar, the second oldest. He, therefore, felt he should have had the next position of authority, and be the Prince of the tribe of Levi. Instead, it went to a man named Elitzafan, who was the son of the youngest brother, Uziel.
In addition, Korach, as a Levi, had to shave off all of his bodily hair. When his wife saw him like that, she convinced him that Moses had made up this law in order to humiliate him. She fed his paranoia by reminding him of the slight of his non-choice as Prince of the Levites. In other words, he was fed a whole lot of jealousy which pushed him to rebellion.
Now, it's not politically wise to rebel on the basis of one's own personal ambitions. One needs a higher cause, and so Korach created a populist movement. "The entire congregation is holy! God is in their midst! Why should you (Moses and Aaron) raise yourselves above the congregation of God?"
In order to amplify his populist complaints, he created a visual stunt. He had 250 people dress up in garments that were entirely made of sky blue coloring. He marched them over to Moses, and asked Moses a question: "do these garments require fringes?" There is a commandment to put fringes on the corners of a four-cornered garment. One of those strings must be of the sky blue coloring. Moses responded that yes, indeed, even if the entire garment is made of sky-blue, it requires the fringes.
Korach mocked this response. "This is illogical," he said, "because if one thread of sky-blue is sufficient to render a garment permissible, then if the garment is entirely made of sky-blue it should certainly be permissible on its own, without additional fringes." In other words, if the people are all holy, there is no need for spiritual leadership. We are all sky-blue, we need no fringes.
All of that being said, I still don't see why a special death needed to be created for Korach and his people. Yes, he was jealous. Yes, he was rebelling. So were the spies, so were those who worshipped the Golden calf. They weren't swallowed up by the ground. Korach and his people were. Why?
There was one other instance when death by burial in the earth was presented. It is not written in the Torah. This story is found in rabbinical commentaries. Who was threatened by this death? The entire Jewish people. At what time? As they were about to receive the Torah at Mount Sinai. The rabbis tell us that God held the mountain above their heads and said, "if you accept the Torah, all will be well. If not, there shall be your graves."
My teacher, Rabbi Aaron Soloveichik, questions the need for such a threat. Didn't the Israelites famously respond to God's offer of the Torah with, "We shall do and we shall learn?" They were eager to receive the Torah! Why threaten them with burial?
Rabbi Soloveitchik suggests a powerful resolution to this question. He explains how the people were glad to receive the Torah… for themselves. They, after all, had witnessed the miracles of the Exodus. For them, faith was easy, and so accepting the Torah was a natural response.
But that generation was reluctant to accept the Torah on behalf of its descendants. They feared that their great-grandchildren, not having seen God's power, might not be willing to observe the Torah properly. Thus, they would be liable to punishment. To protect them, by not obligating them in the first place, the people were not ready to accept the Torah on their behalf. Just for themselves, not for their children.
To this, God says that by not accepting the Torah for their descendants, they are giving away immortality. Their generation will be the only one to keep the Torah, and when they are gone, so shall the Torah in this world be gone. They will figuratively be buried under the Mount Sinai that could've been the beginning of an unbroken chain.
Perhaps this is the danger in Korach's rebellion. By seeking to undermine the authority of Moses and Aaron, by seeking to deny the importance of spiritual leadership, Korach endangers the future of the Jewish people. The Judaism of Korach might last a generation, but no further. Why? Because Torah leadership requires the people to be in a process of constant growth. Leaders are the teachers, and learning is the key to Jewish survival. Education is central to our religion. Our most central prayer is the Shema, which enjoins us to "make (the words of Torah) them sharp in the mouths of your children and children's children."
Korach claimed that a person can achieve sufficient Jewish knowledge and spirituality. Once he reaches that level, further growth, and hence, leadership, become unnecessary. The symbolism of the garment made of sky-blue is a perfect metaphor. Moses's replies to Korach that there is no such thing as a garment that does not require the fringes, the strings that go out of the corners. Those strings symbolize the need for constant growth, for constant perfection. They teach us that a garment, no matter how beautiful, is not complete without something coming out of it.
Interestingly, the sequel to the story of Korach is the story of how the princes of the tribes were instructed to bring their staffs to the tabernacle. They would leave them there overnight, and the staff that would blossom and bloom would be that of God's chosen high priest. Sure enough, it was Aaron's staff that grew almonds and flowers. The Hebrew phrase for this is "Vayatzetz tzitz." The Hebrew word for fringes is "Tzitzit." In other words, Aaron's job is to be the fringes, the leader who helps the people to constantly grow. The commandment of Tzitzit, fringes, is given "to all their (Israel's) generations." In other words, there is something about this mitzvah that relates to the future of the Jewish people through their children.
And, interestingly, the rabbis have a sequel to this entire story about what happened underground. The sons of Korach, who were also swallowed up, did not die. They remained on a ledge beneath the Earth's surface, where, according to Talmudic legend, they can still be heard saying, "Moses is true, his Torah is true, and we are the falsifiers."
Korach's sin was to undermine our spiritual leaders, and remove the need for spiritual growth. Such a Judaism could never last, and thus his punishment of burial was a fulfillment of what God had threatened at Mount Sinai. He refused to accept the Torah for his future generations, and thus he was indeed buried. Our emphasis must always be on education, on transmitting the traditions to the next generation. We are part of the chain, and our Torah leaders are the ones who bring that tradition to us from our ancestors. Without them, if Korach had succeeded, we would've had no one to give us those traditions.
