31-35. There went forth a wind from the Lord, and brought quails from the sea, &c.--These migratory birds (see on Ex 16:13) were on their journey from Egypt, when "the wind from the Lord," an east wind (Ps 78:26) forcing them to change their course, wafted them over the Red Sea to the camp of Israel.
      let them fall a day's journey--If the journey of an individual is meant, this space might be thirty miles; if the inspired historian referred to the whole host, ten miles would be as far as they could march in one day in the sandy desert under a vertical sun. Assuming it to be twenty miles this immense cloud of quails (Ps 78:27) covered a space of forty miles in diameter. Others reduce it to sixteen. But it is doubtful whether the measurement be from the center or the extremities of the camp. It is evident, however, that the language describes the countless number of these quails.
      as it were two cubits high--Some have supposed that they fell on the ground above each other to that height--a supposition which would leave a vast quantity useless as food to the Israelites, who were forbidden to eat any animal that died of itself or from which the blood was not poured out. Others think that, being exhausted with a long flight, they could not fly more than three feet above the earth, and so were easily felled or caught. A more recent explanation applies the phrase, "two cubits high," not to the accumulation of the mass, but to the size of the individual birds. Flocks of large red-legged cranes, three feet high, measuring seven feet from tip to tip, have been frequently seen on the western shores of the Gulf of Akaba, or eastern arm of the Red Sea [STANLEY; SHUBERT].

JFB.