Rashi on Numbers 21:5/רש"י על במדבר כ״א:ה׳

1באלהים ובמשה [AND THE PEOPLE SPAKE] AGAINST GOD AND AGAINST MOSES — They placed the servant on a par with his Master (Midrash Tanchuma, Chukat 19).

2למה העליתנו WHEREFORE HAVE YE BROUGHT US UP — “ye”: they (God and Moses) were both on a par to them.

3ונפשנו קצה AND OUR SOUL LOATHETH — This, too, is an expression for “the shortening of soul” and “rejecting” (not being able to bear the trouble).

4בלחם הקלקל THIS LIGHT BREAD — because the manna was miraculously absorbed into their limbs (and was not execrated) they derisively called it “light”. They said: this manna will at some time or other swell up in our stomachs, for is there any mortal (lit., anyone born of woman) who takes in food and does not eject it? (Yoma 75b; cf. Rashi on Avodah Zarah 5b).