Difference between revisions of "Why Were Nadav and Avihu Killed/2"

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<category>Work Accident
 
<category>Work Accident
 
<p>Nadav and Avihu's actions alone would not have warranted their death, but because they were in the wrong place at the wrong time, they were consumed by Hashem's fire.</p>
 
<p>Nadav and Avihu's actions alone would not have warranted their death, but because they were in the wrong place at the wrong time, they were consumed by Hashem's fire.</p>
<mekorot><multilink><a href="RashbamVayikra10-1-3" data-aht="source">Rashbam</a><a href="RashbamVayikra9-23-24" data-aht="source">Vayikra 9:23-24</a><a href="RashbamVayikra10-1-3" data-aht="source">Vayikra 10:1-3</a><a href="R. Shemuel b. Meir (Rashbam)" data-aht="parshan">About R. Shemuel b. Meir</a></multilink><fn>Rashbam is not explicit, but this is the general direction of his comments.&#160; See also T. Granot, <a href="http://etzion.org.il/he/%D7%A4%D7%A8%D7%A9%D7%AA-%D7%A9%D7%9E%D7%99%D7%A0%D7%99-%D7%92%D7%99%D7%9C%D7%95%D7%99-%D7%9B%D7%91%D7%95%D7%93-%D7%94-%D7%A2%D7%9C-%D7%94%D7%9E%D7%96%D7%91%D7%97-%D7%95%D7%9E%D7%95%D7%AA-%D7%A0%D7%93%D7%91-%D7%95%D7%90%D7%91%D7%99%D7%94%D7%95%D7%90">"פרשת שמיני - גילוי כבוד ה' על המזבח ומות נדב ואביהוא" </a>who elaborates on Rashbam and explains the episode in this manner.</fn></mekorot>
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<mekorot><multilink><a href="RashbamVayikra10-1-3" data-aht="source">Rashbam</a>,<a href="RashbamVayikra9-23-24" data-aht="source">Vayikra 9:23-24</a><a href="RashbamVayikra10-1-3" data-aht="source">Vayikra 10:1-3</a><a href="R. Shemuel b. Meir (Rashbam)" data-aht="parshan">About R. Shemuel b. Meir</a></multilink><fn>Rashbam is not explicit, but this is the general direction of his comments.&#160;</fn> R. Granot<fn>See his article, <a href="http://etzion.org.il/he/%D7%A4%D7%A8%D7%A9%D7%AA-%D7%A9%D7%9E%D7%99%D7%A0%D7%99-%D7%92%D7%99%D7%9C%D7%95%D7%99-%D7%9B%D7%91%D7%95%D7%93-%D7%94-%D7%A2%D7%9C-%D7%94%D7%9E%D7%96%D7%91%D7%97-%D7%95%D7%9E%D7%95%D7%AA-%D7%A0%D7%93%D7%91-%D7%95%D7%90%D7%91%D7%99%D7%94%D7%95%D7%90">"פרשת שמיני - גילוי כבוד ה' על המזבח ומות נדב ואביהוא"</a> where he expands on Rashbam's commentary to the story.</fn></mekorot>
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<point><b>Chronology of the Verses</b> – Rashbam posits that the story of Nadav and Avihu is written achronologically, and really occurred before Hashem's fire consumed Aharon's offerings as described in Vayikra 9:24.&#160; It is on this backdrop that he explains the rest of the story. .</point>
 +
<point><b>The Incense offering</b> – According to Rashbam, Nadav and Avihu were not bringing an unauthorized incense, but the regular offering brought every morning.</point>
 +
<point><b>"אֵשׁ זָרָה"</b> – The brothers' only mistake was in bringing "foreign fire" rather than waiting for Godly fire to consume the incense.&#160; Rashbam explains that although a priest is normally allowed to bring fire of his own (אש מן ההדיוט),&#8206; during the Mishkan's consecration, Hashem had wanted to glorify His name by having all sacrifices be consumed via Hashem's fire.&#160; T. Granot suggests, instead, that the brothers were impatient for Hashem's revelation and tried to "hurry the end".&#160; Either way, the brothers were not intentionally going against Hashem's will.</point>
 +
<point><b>"אֲשֶׁר לֹא צִוָּה אֹתָם"</b> – Rashbam explains that although normally the brothers' actions would have been permitted, on this day, Hashem did not command them to do so.&#160; As such, Nadav and Avihu had no way of knowing that their actions were not desired.</point>
 +
<point><b>"וַתֵּצֵא אֵשׁ מִלִּפְנֵי י"י"</b> – Rashbam identifies this fire with that described in Vayikra 9:24,<fn>To support his claim, Rashbam points to other examples where two verses describe an action which originally appear to be distinct but in reality refer to one and the same event.&#160; See the repeated mention of Moshe relaying the nation's words to Hashem in Shemot 19:8-10 and Micha's interactions with his mother in Shofetim 17:1-3.</fn> claiming that there were not two distinct fires, one that consumed Aharon's offerings on the Outer Altar and another that killed the brothers, but only one.&#160; This fire emanated from "before God", from the Inner Sanctum, where Hashem's presence dwells.&#160; In contrast to most exegetes, Rashbam explains that the godly fire did not come vertically down from the heavens, but horizontally from the Holy of Holes to the Outer Sanctum (where it met the brothers) to the Outer Altar.</point>
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<point><b>Severity of the Punishment</b> – T. Granot</point>
 
</category>
 
</category>
 
<category>Sanctified to God
 
<category>Sanctified to God

Version as of 05:33, 31 March 2016

Why Were Nadav and Avihu Killed?

Exegetical Approaches

This topic has not yet undergone editorial review

Punished for Sin

Nadav and Avihu were killed as a punishment for sin.

Problematic Procedure

Nadav and Avihu did not abide by the proper protocol when bringing the incense offering.

What protocol was done incorrectly? These sources bring an array of possible wrongdoings, including bringing the wrong fire,1 not wearing the proper clothing, failing to wash before service,  or entering the Mishkan while intoxicated.2  Though there is a clear mention of the first wrongdoing, "וַיַּקְרִיבוּ לִפְנֵי י"י אֵשׁ זָרָה", there is no explicit mention of any of the other three.  Nonetheless, the fact that the prohibition to drink wine immediately follows the story might be brought as support that the crime involved drinking.
"אֵשׁ זָרָה"
  • Wrong fire - According to most of these commentators, this phrase describes Nadav and Avihu's main sin, bringing fire from a foreign source.  According to R. Yosef Bekhor Shor, although a priest is normally allowed to bring fire of his own ("מן ההדיוט"),‎3‎‎ on this day Hashem had wanted the sacrifices to be consumed only via His fire4 so as to glorify His name.5  Others might maintain, instead, that the incense offering must always be brought from the Outside Altar (as per Vayikra 16:12),6 but Nadav and Avihu brought it from a regular oven.7
  • Problematic offering –The sources who see other procedural mistakes as the problem might suggest that any sacrifice not brought according to proper protocol is in essence a "foreign fire".
"אֲשֶׁר לֹא צִוָּה אֹתָם" – These commentators can explain this verse in one of two ways, depending on the sin attributed to Nadav and Avihu:
  • Lack of command – Ibn Ezra explains that the verse teaches that the brothers acted according to their own understanding, rather than on Hashem's command. Though Hashem had never prohibited Nadav and Avihu from bringing their own fire on the eighth day, He had not authorized it either.  Accordingly, the sources which view this as the sin will have to explain why the brothers received such a severe punishment.
  • Prohibition – Those commentators who posit that the sin related to clothing, washing or drunkenness might instead explain the verse as if written,"אשר צוה אותם לא"‎8 ("that he commanded not to").  For each of these actions there is an explicit warning in Torah, and as such Nadav and Avihu should have known better.9 
" לִפְנֵי י"י" – Most of these sources would likely explain that " לִפְנֵי י"י" refers to the Outer Sanctum where the brothers brought the incense on the altar.10
What motivated the brothers?
  • Positive intentions – One opinion in the Sifra11 states that when the brothers saw that Aharon had finished his service but Hashem's presence had not descended, they worried and decided to bring fire of their own to help it along.12  Though their intentions were positive, their actions suggested a lack of faith and led to a lessening of God's glory.13
  • Mistake –  According to R"Y Bekhor Shor, Nadav and Avihu simply made a mistake, not realizing that Hashem did not want them to bring of their own fire on this day.14  Other procedural sins might similarly be explained as errors; the brothers were still new to service and not as aware as they should have been. 
  • Negative –  It is also possible that the brothers were simply careless, not giving Hashem's service the attention to detail it deserved.  Similary, they might have been influenced by surrounding modes of worship which might have had different expectations.  Thus, for example, if others worshiped their gods while in a drunken frenzy, Nadav and Avihu might have thought to worship Hasem similarly.  Hashem, though, does not desire such worship.
"בִּקְרֹבַי אֶקָּדֵשׁ "
  • R. Yosef Bekhor Shor asserts that the term refers to Nadav and Avihu, who, despite their error, were still considered close to Hashem.  This would work with all the sources who attribute positive or neutral intentions to the brothers, but makes it difficult to explain the severity of the punishment. 
  • The others might explain, as does Rashbam, that the term refers not to Nadav and Avihu, but to Aharon, who was to sanctify Hashem's name by continuing with Hashem's service and not mourning.
Severity of Punishment
  • Capital crimes – Those who maintain that the sin related to drinking, clothing or washing, can easily explain the severity of the punishment since all these sins are punishable by death.  Even if the brothers motives were not negative, they nonetheless committed capital crimes.
  • Lesson to others –  Those who assert that the sin was bringing a foreign fire that was simply "not commanded" have a harder time explaining the punishment.  R"Y Bekhor Shor and Ralbag maintains that it needed to be severe to teach the nation the importance of being exacting in observing the laws of sacrifices. Seeing how Hashem punished even those who were close to him, taught laymen how much more they needed to fear God.

Breaching of Boundaries

The brothers were killed for reaching beyond what was permitted them in approaching God.

What boundaries were breached? These sources maintain that the brothers erred in bringing an incense offering that they were not authorized to bring, and/or that they came too close to God.
  •  Unauthorized Offering – The sources differ regarding the problem:
    • Extra incense – Many of these sources15 explains that the brothers voluntarily brought their own individual incense offering.16 Since the verse states that "לֹא תַעֲלוּ עָלָיו קְטֹרֶת זָרָה ", any extra incense offering was considered problematic.17
    • Took Aharon's job -– Abarbanel, instead, explains hat the brothers were unauthorized because on the eighth day, Aharon alone was supposed to do all aspects of the service,18 similar to the service of the Day of Atonement which is done by the high priest alone.19  Seforno goes further to suggest that throughout the period of Wanderings in the Wilderness, only the high priest was allowed to bring incense (or perform any other services in the sanctuary) due to Hashem's constant presence on the Tabernacle.20 
  • Coming too close – Commentators offer two possibilities:
    • Entered Holy of Holies – One opinion in the Sifra, Bar Kappara in Vayikra Rabbah, and Abarbanel all fault Nadav and Avihu for bringing their offering into the Inner Sanctum which was forbidden to all but the high priest on the Day of Atonement.  As this is where Hashem's presence is most strongly felt, unauthorized entry was not only prohibited but dangerous. 
    • Saw God – One opinion in Vayikra Rabbah, Tanchuma, Targum Pseudo-Jonathon and Rashi assert that Nadav and Avihu were punished not (only)21 for their actions on the eighth day, but for having seen God at Mount Sinai, as described in Shemot 24.22  One might similarly explain that the problem was seeing God on the eighth day itself; as God's presence had descended on the Tabernacle it is possible that the brothers encountered it upon entry into the Sanctuary.23
"אֵשׁ זָרָה" – According to these sources, this phrase is equivalent to "קטורת זרה", meaning an unauthorized incense offering.  The Biur explains that the term "אֵשׁ" is really just a variation of the term "אִשֶּׁה לַי"י'‏", another name for sacrifices.24
לִפְנֵי י"י – According to many of these sources,25 the phrase refers to the Holy of Holies, the forbidden Inner Sanctum.
"אֲשֶׁר לֹא צִוָּה אֹתָם"
  • Not commanded – According to most of these sources the fact that the incense offering was not commanded is what made it foreign, and therefore problematic. R. Hirsch emphasizes how there is no such thing as subjectivity in sacrificial service; a person cannot act on their own individual desires, but only on the commands of Hashem.26
  • Prohibited  – Chizkuni instead reads the verse to mean "which Hashem commanded not [to bring]", pointing to the prohibition in Shemot 30:9 against bringing a "foreign incense offering".  The brothers were violating an explicit command, and therefore punished.
What motivated the brothers?
  • Zeal for Hashem – According to the Biur, R. Hirsch and R. D"Z Hoffmann the brothers' motivations were pure. They brought the sacrifice out of a desire for closeness to Hashem.27
  • Mistaken – Seforno suggests that Nadav and Avihu mistakenly assumed that just like an incense is burned after the Daily Offering due to its bringing of Hashem's presence, so too on the eighth day after Hashem's fire descended and His glory was revealed, an incense offering was called for.28
  • Honor their father – Hoil Moshe suggests that the brothers were worried about their father's honor.  Seeing that Hashem's glory descended only after Moshe came to the Tabernacle to pray, they thought that others would think that their father was unworthy to brings God's presence.29  As such, they thought to bring an incense to prove that their immediate family, too, was desired by God.
  • Arrogance – Shadal, in contrast, attributes the brothers' actions to excessive haughtiness and a desire not to be overshadowed by their father.30 Since they had not been given any individual service to perform they took upon themselves one of the most precious rituals.
"בִּקְרֹבַי אֶקָּדֵשׁ "
  • Nadav and Avihu were holy – According to the Biur, R. Hirsch and R. D"Z Hoffman, Moshe comforted Aharon in these words, telling him that his sons were among Hashem's most holy. Their actions, though wrong, were motivated by a closeness to God, and not sinful thoughts.  As such, their punishment would bring about more fear of God, sanctifying His name.
  • Even the elite punished – Shadal, who views the brothers more negatively, might explain instead that Hashem referred to the brothers as "קְרֹבַי" only because their position as priests had elevated them closer to Hashem.  This, though, made their fall all the greater.  In punishing them Hashem sanctified himself, showing all that no one is immune to punishment.
Severity of the Punishment
  • Those who assert that the brothers actually saw Hashem's presence can easily explain the brothers' death. This is the consequence of getting too close; as Hashem says, "לֹא יִרְאַנִי הָאָדָם וָחָי".  It is possible that even just entering sacred space is a serious breach and deserves punishment, regardless of a person's motives.31
  • Those who view the sin as relating only to an unauthorized incense might also view it as a serious sin, especially since a "קְטֹרֶת זָרָה" is explicitly prohibited. The Biur, R. Hirsch and Hoil Moshe, nonetheless, assert that the brothers were only punished so severely due to their high stature.  The Biur compares their punishment to that of Moshe and Aharon by the rock, whose sin merited disproportionately severe consequences. He notes that there too the verse states "וַיִּקָּדֵשׁ בָּם".‎32 
Biblical Parallels – Several stories in Tanakh show similar punishments for breach of boundaries:
  • Sinai – In Shemot 19, Hashem repeatedly warns the nation not to get too close to the mountain, telling them "כׇּל הַנֹּגֵעַ בָּהָר מוֹת יוּמָת."
  • Korach – In the story of Korach, like here, unauthorized incense offerings result in death.
  • Uza – In Shemuel II 6, Uza touches the Ark to ensure that it did not fall.  Despite his good intentions, his breaching of boundaries resulted in death.33
The Yom HaKippurim Service – The verses that describe the service of the Day of Atonement  clearly connect it to the deaths of Nadav and Avihu.  Hoil Moshe asserts that the entire service was necessary to cleanse the Inner Sanctum from the impurity caused by the deaths of Nadav and Avihu.  Alternatively, the directives might be coming as a corrective to the sin, teaching Aharon the proper protocol to safely enter the Inner Sanctuary.

Punished for Another's Sin

Nadav and Avihu were killed as a punishment to Aharon for his participation in the Sin of the Golden Calf.

Work Accident

Nadav and Avihu's actions alone would not have warranted their death, but because they were in the wrong place at the wrong time, they were consumed by Hashem's fire.

Chronology of the Verses – Rashbam posits that the story of Nadav and Avihu is written achronologically, and really occurred before Hashem's fire consumed Aharon's offerings as described in Vayikra 9:24.  It is on this backdrop that he explains the rest of the story. .
The Incense offering – According to Rashbam, Nadav and Avihu were not bringing an unauthorized incense, but the regular offering brought every morning.
"אֵשׁ זָרָה" – The brothers' only mistake was in bringing "foreign fire" rather than waiting for Godly fire to consume the incense.  Rashbam explains that although a priest is normally allowed to bring fire of his own (אש מן ההדיוט),‎ during the Mishkan's consecration, Hashem had wanted to glorify His name by having all sacrifices be consumed via Hashem's fire.  T. Granot suggests, instead, that the brothers were impatient for Hashem's revelation and tried to "hurry the end".  Either way, the brothers were not intentionally going against Hashem's will.
"אֲשֶׁר לֹא צִוָּה אֹתָם" – Rashbam explains that although normally the brothers' actions would have been permitted, on this day, Hashem did not command them to do so.  As such, Nadav and Avihu had no way of knowing that their actions were not desired.
"וַתֵּצֵא אֵשׁ מִלִּפְנֵי י"י" – Rashbam identifies this fire with that described in Vayikra 9:24,37 claiming that there were not two distinct fires, one that consumed Aharon's offerings on the Outer Altar and another that killed the brothers, but only one.  This fire emanated from "before God", from the Inner Sanctum, where Hashem's presence dwells.  In contrast to most exegetes, Rashbam explains that the godly fire did not come vertically down from the heavens, but horizontally from the Holy of Holes to the Outer Sanctum (where it met the brothers) to the Outer Altar.
Severity of the Punishment – T. Granot

Sanctified to God

Nadav and Avihu's death was not a punishment but a sanctifying of their souls to Hashem.

Problematic Worship

Nadav and Avihu were punished because of an error in cultic practice.  This position subdivides based on the specific aspect of service that is considered problematic:

Unauthorized Fire

Nadav and Avihu brought the wrong fire for the incense offering.

"אֵשׁ זָרָה" – All these sources maintain that it was this "fire from a foreign source" that was problematic, explaining that Nadav and Avihu erroneously used fire of their own (מן ההדיוט), from a regular oven.  However, it is not explicit what is wrong with this:
  • Not from Hashem's fire – Rashbam and R. Yosef Bekhor Shor explain that although a priest is normally allowed to bring fire "מן ההדיוט",‎38 on this special day of the Mishkan's consecration Hashem had wanted the sacrifices to be consumed only via Hashem's fire39 so as to glorify His name through the miracle.40
  • Not from the Copper Altar - The others might suggest, as does the Raavad,41 that although the priest is commanded to light of his own fire for the Copper Altar, this is not true regarding the incense offering.  Its fire needs to be taken from the Outer Altar (as per Vayikra 16:12) while Nadav and Avihu took it from a regular oven.
  • From the wrong place on the altar – Ralbag goes further to suggest that the brothers might have even taken fire from the Outside Altar, but from the wrong place on it.
"אֲשֶׁר לֹא צִוָּה אֹתָם" – These sources disagree regarding the meaning of this phrase and what it says about the brothers' actions:
  • That was not commanded – Rashbam explains that although normally the brothers' actions would have been permitted, on this day, Hashem did not command them to do so.  Ibn Ezra similarly writes that the phrase means that the brothers acted according to their own understanding, not Hashem's command. Sometimes, acting on the absence of a command is itself problematic, even if unintentional.
  • That was prohibited – R. Yosef Bekhor Shor explains in contrast, that the verse should be read as if written "אשר צוה אותם לא",‎42 that the brothers acted against an explicit prohibition, "לֹא תַעֲלוּ עָלָיו קְטֹרֶת זָרָה". It is not clear if he thinks that this is a second wrong-doing of the brothers (that the offering itself was unauthorized) or if he thinks that the fact that the fire was unauthorized is enough to make the entire offering a "קְטֹרֶת זָרָה".
"לִפְנֵי י"י " – Though all these sources might agree that from a literal standpoint, the phrase simply means "before Hashem", they disagree regarding its specific connotation in its various appearances in the unit:
  • All are geographical markers – According to Rashbam, in each of its appearances the phrase refers to a geographical location, but not to the same one. When the verses states that Nadav and Avihu brought their offering "לִפְנֵי י"י", it refers to the Outer Sanctum, but when it speaks of the fire that came "מִלִּפְנֵי י"י" to consume them, it refers to the Inner Sanctum.  According to him, the fire which killed the brothers is the same godly fire mentioned in Vayikra 9:24 that consumed Aharon's offerings on the Outer Altar.  It did not come vertically down from the heavens, but horizontally from the Holy of Holes to the Outer Sanctum (where it met the brothers) to the Outer Altar.43
  • Action emanating from Hashem – The other sources might suggest that while the phrase "לִפְנֵי י"י" refers to the Inner Sanctum where the brothers offered the incense, the term "מִלִּפְנֵי י"י" that is mentioned in 9:24 and 10:2 more simply means "from God", and connotes a supernatural fire.
  • Spiritual evaluation – Ibn Ezra uniquely understands the phrase "וַיָּמֻתוּ לִפְנֵי י"י" to refer not to a geographical location, but a spiritual one.  The brothers acted and died "before God", thinking that they were doing something pleasing to Him.
What motivated the brothers?
  • Mistake – According to some of these sources,44 Nadav and Avihu simply made a mistake, erroneously assuming that the law regarding "אש מן ההדיוט" that was true on other days would apply to the eighth day as well. The Bavli and Lekach Tov criticize the brothers for making their own assumptions and not verifying with Moshe. 
  • Lack of Faith – One opinion in the Sifra and R. Bachya, instead, explain that the brothers actions stemmed from a lack of faith.  They feared either that no fire would come down, or that there was not enough fire on the Altar to consume everything and thus they brought their own.
"בִּקְרֹבַי אֶקָּדֵשׁ "
  • According to Rashbam, the word "קְרֹבַי " (my close ones) refers not to Nadav and Avihu but to Aharon, who was to sanctify Hashem's name by continuing with Hashem's service and not mourning.45
  • Ibn Ezra and R. Yosef Bekhor Shor,46 in contrast, assert that the term refers to Nadav and Avihu , who despite their error were still considered close to Hashem.
Severity of punishment
  • Lesson to others – Ralbag maintains that the punishment needed to be severe to teach the nation the importance of being exacting in observing the laws of sacrifices.
  • Natural consequence – Drawing on Rashbam's understanding that Nadav and Avihu erred unintentionally and that the fire which killed them was the fire intended to consume Aharon's sacrifices which emanated from the Holy of Holies,47 T. Granot suggests that Nadav and Avihu's deaths be viewed not as a punishment but a "work accident".  Though they mistakenly brought the wrong fire, this in and of itself would not have warranted death.  However, since they were in the wrong place at the wrong time, they were naturally burnt when the fire made its way from the Holy of Holies.48
Context - prohibition to drink wine – According to this approach, the prohibition to drink wine might follow this story not because the brothers sinned in this regard but as another warning of the need to be exacting and careful when serving in the Mikdash.
Yom Kippur Service

Unauthorized Offering

Nadav and Avihu brought a an incense offering that was not commanded.

"אֵשׁ זָרָה" – According to these sources, this phrase is equivalent to "קטורת זרה", meaning an unauthorized (and therefore foreign) incense offering.  The Biur explains that the term "אֵשׁ" is really just a variation of  to the term "אִשֶּׁה לַי"י'‏", another name for sacrifices.50  R. D"Z Hoffmann adds that it was not called a "ketoret" since it was not brought on the incense altar.51
Why was the Ketoret unauthorized?
  • Additional service – Most of these sources view this as an additional incense offering (not that brought every morning)52 that the brothers brought on their own, as individuals and not as representatives of the nation.  Since the verse states that "לֹא תַעֲלוּ עָלָיו קְטֹרֶת זָרָה ", any extra incense offering was considered problematic.
  • Aharon's Job -– Abarbanel asserts that on the eighth day, Aharon alone was supposed to do all aspects of the service,53 similar to the service of the Day of Atonement which is done by the high priest alone.54 According to Seforno, not only on the eighth day but throughout the period of Wanderings in the Wilderness, only the high priest was allowed to bring incense (or perform any other services in the sanctuary).  This was due to Hashem's constant presence on the Tabernacle.
"אֲשֶׁר לֹא צִוָּה אֹתָם"
  • According to most of these sources the fact that the offering was not commanded is what made it foreign, and therefore problematic. R. Hirsch emphasizes how there is no such thing as subjectivity in sacrificial service; a person cannot create their own sacrifice nor act on their own individual desires, but only on the commands of Hashem.55
  • "אֲשֶׁר לֹא צִוָּה אֹתָם""אֲשֶׁר לֹא צִוָּה אֹתָם"
What motivated the brothers? Positive motivation – According to the Biur, R. Hirsch and R. D"Z Hoffmann, the brothers' motivations were pure.  They brought the sacrifice out of a desire for closeness to Hashem.
Mistaken – Seforno suggests that Nadav and Avihu mistakenly assumed that just like an incense is brought after the Daily Offering due to its bringing of Hashem's presence, so too on the eighth day after Hashem's fire descended and His glory was revealed, an incense offering was called for.56Negative motivation– Shadal, in contrast, attributes the brothers' actions to excessive haughtiness and a desire not to be overshadowed by their father.57 Since they had not been given any individual service to perform they took upon themselves one of the most precious.
"לִפְנֵי י"י" – While Seforno assumes that the brothers brought the incense on the Incense Altar in the Outer Sanctum, Abarbanel, the Biur, and R. Hoffmann assume that "לִפְנֵי י"י" refers to the Holy of Holies.  Abarbanel views this as an additional sin, but the Biur explains that this was not yet prohibited58 and as such was not the problem.
"בִּקְרֹבַי אֶקָּדֵשׁ "
  • According to the Biur, R. Hirsch and R. D"Z Hoffman, Moshe comforted Aharon in these words, telling him that his sons were amongst Hashem's most holy.  Their actions were motivated by a closeness to God, and not sinful thoughts. 
  • Shadal, who views the brothers more negatively, could suggest, as does Rashbam, that the term refers not to Nadav and Avihu, but to Aharon, who was to sanctify Hashem's name by continuing with Hashem's service and not mourning.
Severity of punishment – The Biur explains that the brothers were only punished so severely due to their high stature. He compares their punishment to that of Moshe and Aharon by the rock, whose sin also merited a disproportionately severe punishment. He note that there too the verse states "וַיִּקָּדֵשׁ בָּם".

Erroneous Service

Breaching of Boundaries

Coming too close to the presence of God resulted in the brothers' deaths.