Exodus 16:3-4

and the children of Israel said unto them, Would that we had died by the hand of the LORD in the land of Egypt, when we sat by the flesh pots, when we did eat bread to the full; for ye have brought us forth into this wilderness, to kill this whole assembly with hunger. Then said the LORD unto Moses, Behold, I will rain bread from heaven for you; and the people shall go out and gather a day's portion every day, that I may prove them, whether they will walk in my law, or no.