Why is the significance of the fact that Hashem forbade Aharon and his sons to grow their hair long?
Ramban #2, Rashbam and Seforno: A Kohen Gadol is anyway forbidden to show any sign of mourning, 4 and the Pasuk is coming to extend the prohibition to Elazar and Isamar, who had the status of Kohanim Gedolim 5 , since they had been anointed with the Shemen ha'Mishchah, as the next Pasuk says.
Da'as Zekenim: It would look like the Korbanos they offered for the nation were not accepted. Do not say that it is a disgrace if their death is not mourned; the rest of Yisrael will mourn their death.
Refer to 10:4:152:1.
The same applies to the prohibition against tearing their clothes (Torah Temimah, citing Mo'ed Katan, 15a).
See Ramban and Sifsei Chachamim.
However, this D'rashah is only an Asmachta (a support from a Pasuk, since the prohibition for an Avel to cut his hair and the Chiyuv to tear his clothes is only mi'de'Rabbanan [See Ramban]).
See 21:10, 11 (Ramban).
Ramban: This was a Hora'as Sha'ah. During the Milu'im they had the law of a Mashu'ach Milchamah; he does not grow his hair long, tear his clothes or become Tamei for relatives; however, he may not offer b'Aninus.
Why does the Torah see fit to add "v'Lo Samusu"? Is it not obvious?
Rashi: To teach them that if they do let their hair grow long (or tear their clothes) they will be Chayav Misah. 1
Mo'ed Katan (24a): A different Avel who does not grow his hair long or tear his clothes will be Chayav Misah.
Seeing as we always infer positive from the negative, and negative from the positive (See Sifsei Chachamim).
In Mo'ed Katan 15a, the Gemara infers that other Avelim must tear their clothes. Why do we learn (ibid. 21a) from "va'Yikra Es Begadav" (Shmuel 2:12:31)?
Riva citing R. Elyakim: The Gemara prefers to learn from va'Yikra Es Begadav, for from there we learn that one must stand at the time, and the Shi'ur is a Tefach. 1
Perhaps he had a different text there. Our Gemara learns there only standing and a Tefach, but not the Mitzvah of Kri'ah itself! (PF)
Why did Moshe need to forbid them to grow their hair long (30 days growth)? In two weeks will be Pesach. The Regel ends Sheloshim!
Moshav Zekenim: They should not wait until the Regel, for the Regel is in place of 30 days (it would be as if they grew hair for 30 days). Rather, they should shave immediately, before the Regel. 1
He did not say that perhaps they already had more than 16 days growth. Surely they shaved before the Milu'im, to look nice for the Milu'im. (PF)
What is Primah?
RS"R Hirsh, citing Rashi (Sotah 7a), Moshav Zekenim: It is tearing into many pieces.
RS"R Hirsh, citing the Aruch: It is tearing at the seams.
RS"R Hirsh: Regarding Avel, it is tearing without dividing into pieces.
Rashi writes that from "v'Lo Samusu" we infer that if they grow their hair long, they will be Chayav Misah. What do we learn from it according to R. Meir (Kidushin 61a), who does not infer positive from negative?
Shevu'os 36b: Regarding Isur, R. Meir agrees that from the negative you infer the positive. 1
Why did Moshav Zekenim, citing R. Yehudah ha'Chasid, leave this difficult? The Rishonim cite different texts in Shevu'os 36b. However, in all of them, R. Meir infers the positive from the negative for a severe Isur that does not involve money. (PF)
If Aharon and his sons do not fulfill their Mitzvah, why will there be anger on all of Yisrael?
Moshav Zekenim, from Tanchuma (Acharei Mos): Aharon's sons died due to Chet ha'Egel. "Al Kol Devar Pesha" - Yisrael sinned against Hashem. "Al Shor" - for making the Egel (a baby ox). "Al Seh" - Hashem became angry at Seh Fezurah Yisrael. "Al.Salmah" - "Hored Edyecha me'Alecha." "Al Kol Aveidah"- "va'Yigof Hashem Es ha'Am." 1 "Asher Yomar Ki Hu Zeh" - they said "Eleh Elohecha Yisrael" 2 . "Ad ha'Elohim Yavo Devar Sheneihem" - of Hashem and Aharon. "Asher Yarshi'un Elokim Yeshalem Shenayim" - these are Aharon's two children who were burned. If the other sons would die, Midas ha'Din would strike Yisrael, for through them the Egel was made.
Moshav Zekenim #1: If they will be so pained that their hair grows long and their garments are torn, they will not offer Korbanos 3 to atone for Yisrael.
Moshav Zekenim #2: They are Sheluchim of Yisrael. If a Shali'ach Tzibur erred, it is a bad sign for the Tzibur for whom he is an emissary.
Moshav Zekenim citing the Rosh: If you will deviate [from this command] and mourn 4 , the Korbanos you offered for Yisrael will not be accepted.
Perhaps 'Aveidah' alludes to the people who died in the plague. (PF)
Even without pain, if their hair is long or their garments are torn, they may not offer Korbanos! (PF)
Surely the text should say 'Te'avlu' in place of 'Tochlu'. (PF)
Why does it say "v'Chol Beis Yisrael"?
Da'as Zekenim (16:1) and Moshav Zekenim (from Pesikta d'Rav Kahana Acharei Mos 26): This (as opposed to Bnei Yisrael) refers to Besulos who did not marry, for they waited for (hoped to marry) them - "Bachurav Achlah Esh [because] uv'Sulosav Lo Hulalu." 1
Moshav Zekenim: You (Aharon and his sons) need not be pained and cry over Chet ha'Egel, for I already 'collected' from you through the death of Nadav and Avihu. Your brothers Beis Yisrael should mourn and cry, for that sin remains for them for generations - there is no generation without punishment for the Egel.
Pesikta: Nadav and Avihu never married, for they said, who is proper for us? Our uncle is king, our maternal uncle is Nasi, our father is Kohen Gadol, and we are Signei Kehunah.
Rashi writes that from "v'Lo Samusu" we infer that if they grow their hair long, they will be Chayav Misah. In Sanhedrin 83b, we learn Misah for Peru'ei Rosh from Shtuyei Yayin!
Moshav Zekenim (9) #1: The Isur here was not said for all generations.
Moshav Zekenim (9) #2: The one who says that the warning here is for all generations, tearing clothes interrupts between "Al Tifra'u" and v'Lo Samusu". 1
Moshav Zekenim: This is difficult, for we learn Peru'ei Rosh from tearing clothes!