What were they complaining about?
Rashi, Ramban #1 (citing the Mechilta), Rashbam, Seforno and Targum Yonasan: They complained that their food supply had run out, 1 and that they had nothing to eat. 2
Ramban #2 (citing the Ibn Ezra): They complained that they had already been one month out of Egypt, and had run out of bread and had eaten most of their animals; and to purchase food for a nation as numerous as they would be extremely costly.
Ramban #3: Stuck in the desert with no end in sight, 3 they were afraid that they would die of starvation, since it was not possible for an entire nation to survive in a desert. 4
Seforno: And, as Pasuk 3 explains, if Hashem wanted to kill them, it would have been preferable to do so while they were still in Egypt, while they had what to eat - since starvation is a particularly horrific death (see Eichah 4:9).
Rashbam (to 16:3) - They would have been better off to have remained in Egypt, where they would have died a natural death, than to die of starvation in the desert.
Ramban: Which explains why the Pasuk writes "va'Yilonu ... ba'Midbar." Initially, they thought that they would soon arrive at the cities that bordered the desert.
Why does this Pasuk not specify what they were complaining about?
Ramban #1 (refer to 16:2:1:1): Because the problem at this point involved the miracle of the 'cakes' lasting so long, and the Torah does not generally discuss hidden miracles. 1 2: Ramban #2: It actually does specify. Refer to 16:2:1:3 and note.
Refer to Bereishis 46:15:3:1 .
Why did the people blame Moshe and Aharon for their current problem?
Ohr ha'Chayim: They blamed Moshe and Aharon for choosing to lead them via the desert.
QUESTIONS ON RASHI
Rashi writes: "They complained - because the bread had run out." What is Rashi adding to what he wrote on the preceding Pasuk?
Mizrachi: See above, 16:1:1.1:1***, citing Mizrachi - When they complained, the bread had just then run out, and they were not yet even hungry.
