Because the brothers became guilty of being jealous of Joseph and hating him, (as we know from Gen. 37:4 and Gen. 37:11) they became victims of Esau in this world. Since ten of the brothers were guilty of such feelings, the Romans tortured ten outstanding Jewish scholars to death, the ones commonly known as the Ten Martyrs, whom Jewish liturgy eulogized in the poem Eylay Ezkira, recited on the Day of Atonement. The ten scholars involved were reincarnations of the ten brothers of Joseph who had taken part in selling him. This is stated in the book Heychalot.

Rabbi Yishmael said:

The day the instructions came to torture Jewish sages to death was on a Thursday. Originally, four sages were to be arrested, Rabbi Shimon ben Gamliel, Rabbi Yishmael ben Elisha the High Priest, Rabbi Yehuda ben Bava and Rabbi Yehuda ben Damah. Eight thousand scholars in Jerusalem were prepared to offer themselves in lieu of these four leaders. When Rabbi Nechunya ben Hakana realized that the decree would not be revoked, he 'lowered me' to the Merkava [Divine Chariot], and I interceded with the [angel] Sar HaPnim -'Minister of the Interior'- he told me that the Supreme Court in Heaven had decreed that ten eminent scholars were to be handed over to Samael, the Celestial representative of Rome. The reason for the decree was to carry out on the bodies of leaders of Israel the penalty imposed on kidnappers as per: "If someone kidnaps a person, sells him and is found out, he shall be executed." (Ex. 21:16)
[According to Sanhedrin 85, the words 'found out' mean that there were witnesses to the deed already before the sale. Ed.] The Heavenly objective was to wipe out the residual guilt of the brothers…

According to the Kabbalists, the Heavenly objective was to wipe out the residual guilt of the brothers which had not been atoned for when they sold Joseph. We can find numerous allusions in our parasha, which relate to the manner in which these Ten Martyrs were killed. According to tradition, Rabbi Yehudah ben Bava had three hundred lonkuyot, lances, stuck into his body. The word "vayitnaklu", meaning "they conspired to kill him" (Gen. 37:18) is an allusion to this; the letters are simply a re-arrangement of the word "lonkuyot".

Joseph said to his brothers, "As for you, go up in peace to your father." (Gen. 44:17) The word "atem" [meaning "you"] in that context was used advisedly. Joseph meant that the brothers themselves could come to their Father in Heaven safely, i.e. they would not in This World suffer the execution as kidnappers who sell their prey. On a future occasion, however, their reincarnated selves would have to pay for the crime with their lives. The Ten Martyrs mentioned were the ones who had to pay with their lives for that sin which had gone unpunished for so long.

The allusion in the verse just quoted serves some Kabbalists as the reason why Reuben, who had not been a party to the sale of Joseph, was included among those who were executed for the crime. His sin had been of a different nature, namely the incident described involving Bilhah. (Gen. 35:22)

Reuben's own words provide us with a hint of this when he said after discovering that Joseph had been removed from the pit "v'ani ana ani ba/Where can I go to?" Rabbi Abraham Saba in his Tzror Hamor comments on this that the letters in the words "ani" and "ana" are the respective first letters of the verse "E-l nekamot Havayah, E-l nekamot hofiah/G‑d of retribution, Lord, G‑d of retribution, appear!"(Psalms 94:1) The re-incarnations of Joseph and Benjamin were not amongst the Ten Martyrs described.

There is a group of Kabbalists who do not include Reuben amongst the Ten Martyrs, but substitute Joseph as the tenth. Their reasoning is that, after all, Joseph was the root cause of the crime committed against him. It was Joseph's tale-bearing which triggered the brothers' sin. Rabbi Akiva's torture was due to the fact that he represented the Shechinah

I have also heard that some Kabbalists consider that Rabbi Akiva was the re-incarnation of Joseph. This is the reason he is known as Akiva ben Joseph. When we consider that Joseph represents "One", as explained earlier, this is all alluded to in the report in the Talmud that Rabbi Akiva ended his life pronouncing the word "echad", meaning "One", in the "Hear O Israel" prayer. The soul that departed from him at the time would be the soul of Joseph who was "One".

In this connection I have heard a mystical explanation that, in reality, only nine of the Martyrs were reincarnations of people who had lived in a previous period. This was so since neither Reuben, nor Joseph, nor Benjamin had committed that kind of sin. When the brothers included the Shechinah at the time they entered into the conspiracy, Rabbi Akiva's torture was due to the fact that he represented the Shechinah. According to this view the tradition that he ended his life with the word echod is that he ended his life "because of the echad". Rabbi Akiva…more than any other scholar, had penetrated into the hidden aspects of G‑d…

The reason that of all the people it had to be Rabbi Akiva who was singled out to suffer the punishment on behalf of the Shechinah, was that in the course of his studies he, more than any other scholar, had penetrated into the hidden aspects of G‑d. In other words, he had experienced the "wings" of the Shechinah as being immediately above him.

In my humble opinion, this latter tradition need not contradict the statement that Rabbi Akiva was the re-incarnation of Joseph. Inclusion of the Shechinah in the brothers' conspiracy of silence is equivalent to including Joseph, who we have described as a junior merkav, carrier of the Shechinah. Rabbi Akiva was the reincarnation of Joseph, and this is demonstrated by the former's close association with the Shechinah. Joseph was the carrier of the Shechinah when he descended to Egypt, which was the beginning of Jewish exile according to the Zohar. We also have the tradition that when the Jewish people descended into Egypt, the Shechinah accompanied them. (Mechilta Beshalach on Gen. 46:4) Something similar occurred before every other exile; in this particular instance, G‑d inspired Joseph before the rest of his father's family came to Egypt. We see that Joseph's essence was a divinely inspired one, which made him a partner of the Shechinah, for he was the carrier of the Divine Presence. If Rabbi Akiva ben Joseph breathed his last by saying "echad", this means that his soul departed while it was immediately "below the Shechinah".

[Translated and adapted by Eliyahu Munk.]