In ver. 21 the allusion is to the "fire of the Lord," which, according to Numb. xi. 3, burnt in the camp, just before the second giving of quails. It comes in here out of chronological order, for the sending of manna follows it; but the psalmist's didactic purpose renders him indifferent to chronology. The manna is called "corn of heaven" and "bread of the Mighty Ones"--_i.e._, angels, as the LXX. renders the word. Both designations point to its heavenly origin, without its being necessary to suppose that the poet thought of angels as really eating it. The description of the fall of the quails (vv. 26-29) is touched with imaginative beauty. The word rendered above "made to go forth" is originally applied to the breaking up an encampment, and that rendered "guided" to a shepherd's leading of his flock. Both words are found in the Pentateuch, the former in reference to the wind that brought the quails (Numb. xi. 31), the latter in reference to that which brought the plague of locusts (Exod. x. 13). So the winds are conceived of as God's servants, issuing from their tents at His command, and guided by Him as a shepherd leads his sheep. "He let it fall in the midst of their camp" graphically describes the dropping down of the wearied, storm-beaten birds. Vv. 30-33 paint the swift punishment of the people's unbelief, in language almost identical with Numb. xi. 33. The psalmist twice stigmatises their sin as "lust," and uses the word which enters into the tragical name given to the scene of the sin and the punishment--Kibroth-Hat _taavah_ (the graves of Lust). In vv. 32, 33, the faint-hearted despondency after the return of the spies, and the punishment of it by the sentence of death on all that generation, seem to be alluded to. The next group of four verses describes the people's superficial and transient repentance, "When He slew them they sought Him"--_i.e._, when the fiery serpents were sent among them. But such seeking after God, which is properly not seeking Him at all, but only seeking to escape from evil, neither goes deep nor lasts long. Thus the end of it was only lip reverence, proved to be false by life, and soon ended. "Their heart was not steadfast." The pressure being removed, they returned to their habitual position, as all such penitents do.