What is the difference between "Besamim" (Pasuk 23) and "Samim"?
Why does the Pasuk refer to Tzari (balsam) as "Nataf" (which means 'drips')?
Rashi and Ramban #1 (citing Kerisus, 6a): Because it is the sap that drips from the wood of the balsam-tree (Atzei ha'Kataf), which is also called 'T'ri'akla'. 1
Rashi. See Ramban, who vehemently refutes this translation. He also presents another reason as to why the Torah calls it "Nataf" (See DH 'Aval ha'Tzari'). The Ramban also cites Targum Onkelos (and Targum Yonasan according to our text [See Ramban, Ibid.]) who translates "Tzari" (in Bereishis 37:25) as 'Kataf', implying that, according to them, both the tree and its fruit are called 'Tzari'.
See Ramban, DH 've'Ra'isi'.
Despite the expression "Nataf".
Why does Onkelos translate "Shecheiles (onycha) as 'Tufra' (finger-nail)?
Rashi: Because it is smooth and shiny like a finger-nail. 1
Which also explains why the Mishnah in Kerisus refers to it as 'Tziporen'.
Why does the Torah include the foul-smelling Chelbenah (galbanum) in the middle of the spices of the Ketores?
Rashi: To teach us that we should not hesitate to include sinners (who have done Teshuvah) 1 in our groups of those that fast and pray.
Michtav me'Eliyahu (5, p. 416): Chelbenah does not have a nice smell, but it is potent (Radvaz). To reach Deveikus, one needs a string desire to overcome and nullify all other desires. Even if at the time he does not feel the sweetness, combined with all the other ingredients, the uneasiness is Batel, and the wondrous scent is strengthened even more.
See Sifsei Chachamim.
How many ingredients did the Ketores comprise?
Rashi and Ramban #2: "Samim" = two; plus Nataf, Shecheiles and Chelb'nah = five; Samim - another five = 10, plus Levonah Zakah (pure frankincense) = 11. 1
Ramban #1 (citing Ibn Ezra) and Rashbam: "Samim" - Nataf, u'Shecheiles ve'Chelb'nah, and pure frankincense = four. 2 And the second "Samim" is merely a repetition of the first "Samim", as is the way of the Torah. 3
The Gemara in Kerisus lists the remaining seven as Mor (myrrh), Ketzi'ah (cassia) Shiboles-Nerd (spikenard) and Karkom (Saffron) Kosht (kostus) Kilufah (cinnamon) and Kinemon (cinnamon bark). See also Ba'al ha'Turim on Pasuk 37.
Presumably, the Torah leaves the other seven up to the Chachamim to add as they see fit (Refer to 30:34:8:1).
Mor, Kineman-Besem (Kinamon), K'nei-Bosem (Kilufah) and Kidah (Ketzi'ah).
Which enhance the other ingredients (See Seforno).
Why do the Chachamim not include Boris Karshinah (vetch) as a twelfth ingredient?
Rashi: Because it was not burned together with the other spices, but was used to whiten the Shecheiles (to give it a nice appearance). 1
What does "Bad be'Vad" mean?
Rashi: It means that all four specified ingredients consisted of the same weight - seventy Manah. 1
Da'as Zekenim, Hadar Zekenim #1: Each must be weighed [on the balance scale] against weights, and not against another ingredient that was already weighed against a weight.
Hadar Zekenim #2: One may not put weights one inside another to weigh against the ingredients. 2
Why does the Torah not name the other seven ingredients?
Ramban #1 (citing Midrash Chazis): The Torah is only particular about these four, which are crucial to create the required pillar of smoke. As for the remaining seven, it leaves it up to the Chachamim to add what druggists tend to add to create a pleasant aroma. 1
Ramban #2: It is possible that Hashem informed Moshe on Har Sinai which other ingredients to use - as well as how to prepare them. 2
The reason that the Chachamim chose Nerd, Karkom and Kosht (Ohalos) is because the Pasuk mentions them in Shir ha'Shirim, 4:14 (Ramban), and they included Kaneh, Kinmon, Levonah and Mor because they comprised the ingredients of the Shemen ha'Mishchah - See Ramban DH 've'Nir'eh li', who elaborates.
Just as He taught him how to prepare the Shemen ha'Mishchah (Ramban).