This week's Torah reading begins with the death of two of Aaron's sons after they entered the Holy of Holies uninvited and offered incense they had not been commanded to bring. The sages of the Zohar in the following piece disagree as to the ramifications of this transgression.

The sons of Aaron, Nadab and Abihu, each took his fire pan, put fire in them and placed incense upon it. They brought before G‑d an alien fire that He had not commanded them. A fire came forth from before G‑d and consumed them, and they died before G‑d. (Lev. 10:1-2)

Rabbi Chizkiyah said:…Aaron's two sons offered alien fire [the external forces latched onto their service and therefore] they did not unify the Name of G‑d as is proper and they were burned by fire.

They were punished for their transgression. (Ramak, Mikdash Melech)

Aaron's sons…died two deaths….

Rabbi Yitzchak said: It is written: After the death [of two of Aaron's sons]… and they died. (Lev. 16:1) Since the verse states, "…after the death of two of Aaron's sons," don't I know that "they died"? [In other words, why does the verse repeat that they died?] However, this is what we learned: They died two deaths - one "before G‑d" [this is the death of the soul] and the other, that they had no children [this is the death of the body] for one who has no children is regarded as dead. (Nedarim 64b)

Rabbi Abba [disagreeing with the above opinions] said: What then, is the meaning of this verse: "Nadab and Abihu died before G‑d when they offered an alien [i.e. unauthorized] fire to G‑d in the Sinai desert. They had no children, so Elazar and Itamar served as priests during their father Aaron's lifetime". (Num. 3:4) What does one thing - that they had no children - have to do with the other, namely Elazar and Itamar serving as priests?

However, the secret is this: They died [the death of the body] because they did not have children, this is certain. But unlike other people [where a childless person is regarded as dead] even though they were unmarried [otherwise they could have been rectified through the process of levirate marriage, called "yibum" (See Zohar, parashat Mishpatim)], they nevertheless only experienced physical death, but not the death of their souls [which became impregnated in Pinchas, as we will see shortly].

From where do we know this? It is written: "Elazar, Aaron's son, married one of the daughters of Putiel, and she bore him Pinchas. These are the heads of the Levite clans according to their families". (Ex. 6:25) "These are"? The verse speaks only about Pinchas, and nevertheless it states, "These are the heads of the Levite clans!" This is because they [Nadab and Abihu] only underwent the death of the body but not of their souls.

These souls were impregnated into the soul of Pinchas in the secret of ibbur, an aspect of transmigration of souls. And this is why the verse "they had no children" is followed by "so Elazar served as priest…." (Ramak, Mikdash Melech)

They had not yet taken wives and therefore they are regarded as incomplete…

Rabbi Elazar added: The verse certainly implies this, since it states "these are" and "the heads" [both are in the plural]. And [another explanation is] this is why it is written "Pinchas the son of Elazar, the son of Aaron the Priest…"; (Num. 25:11) it would have been sufficient to say, "Pinchas the son of Elazar, the Priest." However, wherever Pinchas is mentioned [in the Five Books of Moses] he is always referred to as [the son of Elazar,] the son of Aaron the Priest.1

In other words, the Torah always explicitly identifies Pinchas as "the son of Aaron the priest", because he can be regarded as a son by virtue of the souls of Aaron's sons impregnated into his.

The reason for this is again because they only underwent the death of the body but not of their souls…

Rabbi Elazar asked his father [Rebbe Shimon]: But they were two [men, Nadab and Abihu] so why were there not two [separate ibbur's, one in Pinchas and one in someone else?] Rabbi Shimon replied: they were two parts of a single whole, for they had not yet taken wives and therefore they are regarded as incomplete. For this reason they are incorporated into only one person - Pinchas. This then is the secret of the verse: "she bore him Pinchas [in the singular]; these are the heads of the Levite clans [in the plural]."

They did not sin as such, and therefore their souls survived. They were, however, incomplete in terms of their bodies, since they had not married. Rabbi Yose goes even one step further: if there is any criticism of Nadab and Abihu at all, it has been completely atoned for.

The death of Aaron's sons atones for Israel….

Rabbi Yose taught: [The Sages] established the practice of reading this portion on Yom Kippur as atonement for the Jewish People in exile [since we do not have the Holy Temple and cannot bring sacrificial offerings as an atonement, as the Zohar explains (Vol. III:56b)]. The reason for establishing this practice on Yom Kippur is because the death of Aaron's sons atones for Israel. From this we learn that any person who's Master sends him suffering - this suffering atones for his sins. In addition, anyone who is distressed by the suffering of the righteous has his sins removed from the world. Accordingly, we read about the deaths of Aaron's sons so that the people will hear and be distressed at the passing of the righteous, and this will atone for their sins. In fact, in regard to anyone who is distressed by the passing of a righteous person, or who sheds tears over them, the Holy Blessed One declares, "Your sin has been removed; your transgression has been atoned for". (Isaiah 6:7)

In other words, not only was their "sin" atoned for by their death, but their death takes the place of the sacrifice of atonement of Yom Kippur, and purges our sins as well.

[Zohar III, 57a-b; translation and commentary by Moshe Miller]