Numbers 21:4,5

And they journeyed from mount Hor, by the way of the Red sea— Houbigant supposes that the word, which we render the Red-sea, im-suph, is one word, denoting some principal place in that country; and so, accordingly, he renders it, upon the supposed impossibility of the Israelites passing again by the Red sea. In this journey, the soul of the people was much discouraged; i.e. made fretful and impatient through fatigue; when, like their forefathers, they began to murmur against God, and reflect upon Moses: not hesitating in their impatience to utter the greatest falsehoods; for there is no bread, neither is there any water, say they, (Numbers 21:5.) though they were fed with bread from heaven, and water from the rock. They did not consider that which God gave them as worthy the name of bread: our soul loatheth this light bread; this exceeding vile and contemptible bread, as the Hebrew word expresses it; or, as the LXX has it, this empty bread; having no substance in it to give solid nourishment. See ch. Numbers 11:6.

See commentary on Numbers 21:9