Who were the "Safsuf"?
Rashi #1: Targum Onkelos and Targum Yonasan They were the Eirev Rav, who joined them ('she'Ne'esaf lahem') when they left Egypt. 1
Rashi #2 (in Divrei Hayamim 1, 2:6), Da'as Zekenim (in Pasuk 13, citing R. Sh'man bar Aba or R. Shimon ben Menasya): They were the Zekenim (the Sanhedrin). 2
Da?as Zekenim: They should have died at Matan Torah, but Hashem delayed their death until now. That is why Moshe said (in Pasuk 14) 'I cannot bear this nation alone' - because, until then, the Sanhedrin bore with him.
Like the Torah writes in Pasuk 16 "Esfah Li Shiv'im? Ziknei ha'Am". (Rashi and Da?as Zekenim).
What were the Safsuf grumbling about?
Rashi and Seforno: They were grumbling about a lack of meat. 1
Ramban: They lacked nothing. They had the Manna, which satisfied them and from which they were able to prepare foods with the most exquisite taste. They deliberately worked up a powerful desire 2 for nothing in particular - like a person who wants to eat coal and rotten food.
Seeing as they possessed a lot of animals (See Sh'mos 12:38), and they received the S'lav [every night], and they could taste whatever they wanted in the Manna (Va'yiten lahem She'elasam ?Tehilim 106:15), why were they grumbling "Who will feed us meat"?
Rashi: They were only looking for an excuse to complain, so they picked on a lack of meat in order to give vent to their frustrations. 1
Ramban: Granted, the people ate meat from time to time; some of them even possessed animals. Nevertheles, they grumbled because they did not eat meat every day. 2
Seforno: Their official complaint this time ("Vayashuvu Vayivku ... ") was why Hashem took them out of Egypt, 3 in total rejection of the benefit of having the Shechinah in their midst. 4 However, they based their complaint on a test to see whether Hashem could or would provide them with meat 5 (notwithstanding the fact that they had animals). 6
Moshav Zekenim: They were testing whether Hashem had power to provide their request. 7
Da'as Zekenim (in Pasuk 13, citing Bamidbar Rabah): They grumbled amidst desire for [a Heter for] Arayos (?She'er Besaro? ? Vayikra 18:6) 8 .
Riva (in Sh'mos 16:13, citing R. Yitzchak): The S'lav 9 ceased in the first year. It says only (in Sh'mos 16:35) that B'nei Yisrael ate Manna for forty years, and (in Yehoshua 5:12) that the Manna ceased.
Refer to 11:1:2:1 - as Chazal said in Avos, 4:2, 'Aveirah Goreres Aveirah' ('One sin leads to another').
See Ramban, Sh'mos 16:2 and R. Chavel's footnotes.
Seforno: See Pasuk 20.
As the Pasuk explains in Tehilim, 78:18, 20.
See also Ba'al ha'Turim.
As the Pasuk writes in Tehilim 78:18"Vaynasu Keil bi'Levavam".
As the Pasuk writes in Tehilim 78:27 - "Vayamter aleihem ke'Afar She'er.".
He does not address that they had animals. Perhaps they already ate most of the Kosher animals that they took from Mitzrayim, or the animals died - when there was a lack of water. We find only that B'nei Gad and B'nei Reuven had much flock. (PF)
Why does the Torah write "Vayashuvu Vayivku ... "?
Ramban (in Pasuk 1): They did not learn a lesson from the result of their first unjustified complaint, and proceeded to grumble again, this time about their limited pleasures in the desert. 1
Seforno: Once again, 2 they grumbled, not because they had reason to, but in order to test Hashem.
Why did they ask for meat, seeing as they had the S'lav (quails) ? See Sh'mos 16:8)? And why there does the Torah not mention wind, whereas here it does?
Moshav Zekenim: Before, they were near the sea, the habitat of S'lav, and wind was not required. Here they were far from the sea, and doubted Hashem's ability to bring S'lav from afar.