Koraḥ the son of Yitzhar, the son of Kehos, the son of Levi took [himself to one side] along with Dasan and Aviram, the sons of Eliav, and On the son of Peles, descendants of Reuven.

Num. 16:1

There is a curious aspect to the story of Koraḥ’s rebellion. We can understand why Koraḥ (or Korach), being of the tribe of Levi, may have had a claim to the priesthood thus causing a rebellion against Mosheh and Aaron HaKohen, the High Priest.  The Torah tells us, however, that some Reubenites, that is, members of the tribe of Reuven, got entangled with the followers of Koraḥ in this rebellion as well.  But what did they have to do with it?  Not being descendants of Levi, they surely had no claim on the priesthood.  Why did they entangle themselves with the Levites, the followers of Koraḥ, when they had no dog in that fight?

Rabbi Yisroel Charif of Satanov, one of the disciples of the Baal Shem Tov, asks this question in his book, Tiferes Yisroel.  He offers a fascinating answer:

There is a Biblical obligation to tithe produce—to give one tenth of one’s harvest to the Levites—members of the tribe of Levi who did not get an ancestral portion of land in Eretz Yisrael (the Land of Israel), as all other tribes, but survived on these tithes (in Heb., ma’aser) brought to them by the Israelite farmers.

Any tithe of the Land, whether it be from the seed of the land or the fruit of the tree, it is the Lord’s.  It is holy to the Lord… Any tithe of cattle or flock, of all that pass under the rod, the tenth shall be holy to the Lord.

Lev. 27:30,32

While the law only requires tithing the produce, on a spiritual level, the concept of tithing applies to everything one is blessed with, including one’s children.  Thus our patriarch, Jacob, intended to give the tithe (ma’aser) from his twelve sons.  How does one give a tithe from children?  By dedicating one tenth of them to the service of G‑d.  Indeed, Jacob dedicated his son Levi to the service of G‑d:

As for Me, I have taken the Levites from among the children of Israel in place of all firstborns among the children of Israel who have opened the womb, and the Levites shall be Mine.

Num. 3:12

The tribe of Levi was dedicated to the service in the Temple—Bet HaMikdash

The ma’aser (tithe) is one tenth. At the first blush, it appears that Yaakov did not give enough ma’aser, as one-tenth of twelve is 1.2, which is more than the one son that he dedicated to G‑d.  That would have been a problem indeed, were all twelve of his sons had been the subject of tithing.  However, this was not the case.  Recall that the firstborns belong to G‑d to begin with, as it says:

For all the firstborns are Mine; since the day I smote all the firstborns in the land of Egypt, I sanctified for Myself all the firstborns of Israel, both man and beast they shall become Mine, I am the Lord.

Num. 3:12

and

Sanctify to Me every firstborn, every one that opens the womb among the children of Israel among man and among animals; it is Mine.

Ex. 13:2

Only a non-firstborn (in Heb., a pashut) is subject to the tithe. Additionally, from the latter verse, we learn that a firstborn is the one who “opens the womb.”  Someone with more than one wife may, therefore, have more than one firstborn.  Jacob had four wives: Leah, Rachel, Bilhah, and Zilpah.  Each had a firstborn son.  Thus Yaakov had four firstborns: Reuven (the firstborn of Leah), Joseph (the firstborn of Rachel), Dan (the firstborn of Bilhah), and Gad (the firstborn of Zilpah). (see Gen. 35:23-26.) Therefore, only the remaining eight (twelve less four firstborns) sons of Jacob were subject to the tithe.  Consequently, by dedicating Levi to the service of G‑d, Yaakov gave more than the required tenth (which would have been 0.8), rather than less.

But why is that a problem?  Surely, giving more charity than necessary is a good thing!  It turns out, however, that ma’aser—tithing—is not a charity, but a biblical obligation to give one-tenth, no less and no more.  The Talmud explains that when less than one-tenth is given, the unseparated part gets entangled with the rest of the produce making all of it unfit for consumption. Say, the produce was 100 pounds of grain requiring 10 pounds to be given as the ma’aser.  Before the ma’aser is separate, the produce is called tevel.  After the ma’aser is separated (or when it is not required) the produce is called chulin.  Say, only 9 pounds out of 100 were separated and given to a Levite—one pound less than the required one-tenth.  This pound of ma’aser that was not given to a Levite is now mixed with 90 pounds of chulin.  Thus, the remaining 91 pounds of grain is not chulin, but is a mixture of chulin and ma’aser.  Every grain is, therefore, in a blurred state of superposition of two states: chulin and ma’aser.  Similarly, if one gives more than one tenth to a Levite, that Levite cannot use it, because the excess portion, which was tevel, is not holy and gets entangled with the rest of the ma’aser making it all unfit for consumption by the Levite.  Again, every grain is now in a blurred state of superposition of two states: ma’aser and tevel.  That is why the Sages of the Mishna said:

Do not accustom yourself to tithe by estimation.

Pirkei Avot 1:16

But didn’t Jacob know all of this?  How then he gave more ma’aser than necessary?  What was his calculus?

The Kabbalah teaches that Jacob was destined to have two more sons born to him from his concubine Bilhah. The souls of Jacob’s two unborn sons were hovering over his bed, as it were, ready to be born, when Reuven interfered.  The Torah says:

And it came to pass when Israel sojourned in that land, that Reuven went and lay with Bilhah, his father’s concubine, and Israel heard [of it], and so, the sons of Jacob were twelve.

Genesis 35:22

The sages are inclined to interpret this text allegorically.  Reuven stood up for his mother’s honor and moved Yaakov’s bed into Leah’s tent where, he thought, it belonged.  This act was so disrespectful to his father that the Torah qualifies it as a carnal sin.  What is most interesting here, however, is a sudden juxtaposition of the phrase, “and so, the sons of Jacob were twelve,” which contextually does not belong there.  It is if the Torah wants to tell us that, but for the sin of Reuven, there would have been more sons born to Jacob, but now, there would be only twelve! Indeed, this was the case. These two souls were not born to Jacob.

Were these two sons born to Jacob as destined, he would have had fourteen sons in all, four of which would have been firstborns, leaving ten subject to tithing.  In that case, Levi would have been precisely one-tenth of Jacob’s sons (not counting the firstborns) and a perfect tithe (ma’aser).  Jacob’s calculation would have been correct.  Alas, Reuven interfered with the destiny.

What happened to those two souls?  Eventually, these two souls intended to be born to Jacob, were instead born in Egypt to Jacob’s son Joseph.  This is why, when Joseph first introduces his sons, Menashe and Ephraim, to his father, Jacob tells him:

And now, [as for] your two sons, who were born to you in the land of Egypt, before I came to you, to the land of Egypt, they are mine. Ephraim and Manashe shall be mine like Reuven and Shimon.

Genesis 48:5

The consequences of Reuven’s sin continued to ripple through the Jewish history.  By spoiling Jacob’s ma’aser, which was now more than required, Reuven caused the tribe of Levi to contain an admixture of commoners, because it was now entangled with the other tribes.  This unholy element manifested in the rebellion of Koraḥ.  Koraḥ and his cohorts from the tribe of Levi were the unholy elements in the tribe of Levi resulting from the “extra ma’aser” unintentionally given by Jacob.  Reuven, who caused this imbalance through his sin, became “entangled” with Levi and, consequently, his descendants aligned themselves with Koraḥ against Moshe and Aaron who epitomized the holy element of the Tribe of Levi.

Death_of_Korah_Dathan_and_Abiram
Death of Korah, Dathan and Abiram, Gustave Doré, 1865.