Why does the Torah specifically address Aharon and his sons?
Oznayhim la'Torah: Although B'nei Yisrael are basically the ones to declare Nedarim and Nedavos, the Kohanim, who bring them on the Mizbe'ach, are being warned not to accept the Ba'alei-Mumin that the Yisrael brings. 1
See Oznayim la'Torah.
Why does the Torah repeat the word "Ish"?
Having included Nochrim in the realm of Korbanos, why does the Torah see fit to add "u'min ha'Ger be'Yisrael"?
Sifra: "ha'Ger" comes to include the wives of Geirim and "be'Yisrael", women and Avadim, rendering them equal to men in all respects. 1
See Torah Temimah, note 106.
What is the difference between Nedarim and Nedavos?
Rashi and Ramban #1 (citing Kinim, 1:1): Neder is when a person says 'Harei Alai'; Nedavah, when he says 'Harei Zeh'. 1
Ramban #2: One usually declares a Neder when one is in trouble and requests Divine assistance 2 - which explains why the Lashon 'Pele' generally accompanies Nedarim. 3
Ramban: Which he designates and brings immediately. Consequently, he is responsible for the former (to replace it should it die or get stolen), but not for the latter. See also Torah Temimah, note 108
Refer also to 28:18:152:1.
See Ramban.
Why does the Torah add "le'Chol Nidreihem u'le'Chol Nidvosam"?
Ramban: To teach us that even a Nedavah, which one donates when not under duress, 1 must be without a blemish.
Seforno: To disillusion those who think that, since they volunteered to bring the Korban Olah, they are entitled to bring a Ba'al-Mum should they so wish. 2
Nazir, 25a: On the other hand, the Torah compares them them, to teach us that the remains of a Neder is brought on the Mizbe'ach as a Nedavah. 3
Seforno: The Pasuk therefore teaches us that this is a fallacy, since, if one would not bring a blemished animal to one's king, how much more so to Hakadosh-Baruch-Hu, as the Pasuk writes in Mal'achi, 1:8.
See Torah Temimah, note 107.
Seeeing as the Torah is discussing a Korban Yachid, why does it write "asher Yakrivu" (plural)?
Menachos, 104b: To teach us that all Korb'nos Nedavah 1 can be brought be'Shutfus.
See Torah Temimah, note 109.
Why does the Torah add the word "le'Olah"?
Refer to 22:18:1:1**.
Yerushalmi Shekalim, 4:5: To teach us that all Ba'alei-Mumin that are redeemed are brought as Olos Beheimah ? except for birds, since the next Pasuk writes "ba'Bakar ba'Kesavim u'va'Izim". 1
See Torah Temimah, note 110.
Why can Nochrim bring only Olos and not Shelamim?
Rashi (in Menachos, 73a): Because when a Nochri brings a Korban, he brings it with the intention of giving it to Hashem (not of eating it himself ? like a Shelamim).
Oznayim la'Torah: Because a Shelamim is eaten by the owner and a Nochri is forbidden to eat Kodshim. 1
See Oznayim la'Torah, DH 'le'Olah'.
What is the connection between the previous Parshah and the following one?
Seforno: The previous Parshah discussed the Dinim concerning the people bringing the Korbanos, whereas the following one discusses the equivalent Dinim concerning the Korbanos themselves.
Rashi (on Pasuk 25) writes that "Ish Ish" includes Nochrim in the Dinim of Nedarim and Nedavos. We should know this already, since the Torah writes in connection with Mumim "u'mi'Yad Ben Nechar Lo Sakrivu", implying that one may offer unblemished animals on their behalf?
Riva (on Pasuk 25) #1: If not for "Ish Ish", one might have thought that one who offers a Tam for a Nochri transgresses an Asei, and for a Ba'al Mum there is also a Lav.
Riva (on Pasuk 25) #2: If not for "Ish Ish", one might have thought that Nochrim may offer even Chata'os and Ashamos. The Pasuk teaches that a Tam for a Nochri transgresses a Lo Sa'aseh.
Moshav Zekenim citing Ri: Nochrim may offer a Ba'al Mum on a Bamah. "U'mi'Yad Ben Neichar" is not extra; it is needed to teach that they cannot offer it in the Mikdash. 1
Even if it is not extra, we can infer that they can offer Nedarim and Nedavos! (PF)
Why does the Torah write "Lefalei Neder"?
Ramban and Moshav Zekenim: A Neder is a vow that one makes when things are Nifla'im (hidden) from them, and they promise to bring an Olah or Shelamim if He performs with them a Pele (a miracle) and delivers them from their troubles. 1
We find "Lehafli Neder" also below in 27:2 and in Bamidbar 6:2. See also Bereishis 28:20 and Bamidbar 21:2.