Why does the Torah here refer to Yaakov's 70 descendants as "Nefesh" (singular), whereas in Parshas Vayishlach (Bereishis 36:6) it refers to Esav's six children as "Nefashos" (plural)?
Rashi (to 46:26): Because Esav's children worshipped a variety of gods, whereas Yaakov's worshipped only one G-d.
Here the Torah lists 70 descendants of Yaakov. In Parshas Pinchas (Bamidbar 26), only 65 families are listed!
Peninim mi'Shulchan ha'Gra (8): Here, the 70 1 include Yaakov's 12 sons, Efrayim and Menasheh, and three females. None of them are called families there. There, it lists 12 families from Efrayim and Menasheh, and an additional five from Levi. This would complete 70, but five families are missing - Ohad from Shimon, Gera, Becher and Rosh from Binyamin, 2 and Yishvah from Asher.
Peninim mi'Shulchan ha'Gra: The 70 correspond to the 70 facets of Torah; the 49 from Leah and her Shifchah correspond to the 49 facets of Torah. (The Yerushalmi Sanhedrin 4:2 learns 49 facets from "Imros Hashem... Shiv'asayim" - Tehilim 12:7). Each wife had in all twice as much as her Shifchah (without counting Yocheved. In other cases as well, we find twice as many from wives as from Shefachos or concubines - refer to 22:20:4:1.) (PF)
Rashi (to Bamidbar 26:13, citing the Yerushalmi): Due to a civil war after Aharon's death, seven families are missing, including five from Binyamin. I.e., the Torah (ibid.) lists families of Bela's sons Na'aman and Ard, but the families Na'aman and Ard, Bnei Binyamin, were lost. The Gra does not mention them, for the lost families were replaced by new families with the same names. (PF)
There are various opinions as to who is counted as the "seventieth soul." What is behind this discussion?
Maharal (Gevuros Hashem Ch. 13, p. 68): The last unit included in a count may be distinct from the other units. It is included merely to complete the total number. 1
A) Some say it was Yocheved - who was born just then. B) It was Yaakov - although not counted among his descendants, he completed their number of 70. C) Hashem is the completing factor (Kolel) of Am Yisrael. D) It was Chushim, son of Dan; the rearguard of the tribes (Bamidbar 10:25). E) It was Serach, daughter of Asher, (granddaughters are usually not mentioned, they are secondary to the sons).
Why did Am Yisrael begin with the number 70?
Maharal (Gevuros Hashem, Hilchos Yayin Nesech, p. 334): 70 is the Gematriya of the word "Sod" (secret). Am Yisrael started with 70, opposite the seventy distinct nations, to highlight how Am Yisrael would have a different essence.
Why did Am Yisrael descend to Mitzrayim, specifically at the time that they reached the number seventy?
Maharal #1 (Gevuros Hashem Ch. 9, p. 54): With the number 70, they had a point in common with the 70 nations. Only now that they were in opposition, was it possible to become subjugated to Mitzrayim. 1
Maharal #2 (Gevuros Hashem, Hilchos Yayin Nesech, p. 333): See above, 46:27:151.3:1. Had the number of 70 been completed prior to their entry into Mitzrayim, Am Yisrael would have had their initial start even before their sojourn there. Had they reached 70 only after their entry, that would mean that Bnei Yisrael became subjugated before the proper time. Thus, Yocheved was born precisely as they entered the walls of Mitzrayim.
Maharal #3 (Chidushei Agados Vol. 3, p. 126, to Bava Basra 123a): At seventy souls, Am Yisrael was considered a nation. Am Yisrael in Mitzrayim was akin to a developing fetus inside of an animal. 2 Had they reached the number seventy prior to their descent, they would be like a fetus outside of the animal (i.e. they would lack the environment they needed in which to grow). Had they come without 70, they would lack their own identity, and be subsumed among the Egyptians.
Also refer to 46:4:1.2:1. Also see Maharal (Gevuros Hashem Ch. 11, p. 64).
See Maharal (Gevuros Hashem Ch. 3) for more on this comparison.
