Exodus 16:2-5

2 In the desert the whole community grumbled against Moses and Aaron.
3 The Israelites said to them, “If only we had died by the LORD’s hand in Egypt! There we sat around pots of meat and ate all the food we wanted, but you have brought us out into this desert to starve this entire assembly to death.”
4 Then the LORD said to Moses, “I will rain down bread from heaven for you. The people are to go out each day and gather enough for that day. In this way I will test them and see whether they will follow my instructions.
5 On the sixth day they are to prepare what they bring in, and that is to be twice as much as they gather on the other days.”