Wherefore hast thou afflicted thy servant? These passionate complaints were clearly wrong, because exaggerated. God had not thrown upon Moses the responsibility of getting the people safely into Canaan, or of providing flesh for them; and apart from these exaggerations, it was a selfish and cowardly thing thus to dwell upon his own grievance, and to leave out of sight the grave dishonour done to God, and the awful danger incurred by the people.
It was the more blameworthy in Moses because upon a former occasion he had taken upon him, with almost perilous boldness, to remonstrate with God, and to protest against the vengeance he threatened to inflict (Exodus 32:11-13).
In a word, Moses forgot himself and his duty as mediator, and in his indignation at the sin of the people committed the same sin himself. It is a strong note of genuineness that so grave (and yet so natural) a fault should be recorded with such obvious simplicity.
Compare the eases of Elijah (1 Kings 19:1-21) and of Jonah (Jonah 4:1-11).