And as Aaron spoke to the whole congregation of the people of Israel, they looked toward the wilderness, and behold, the glory of the Lord appeared in the cloud. And the Lord said to Moses, “I have heard the murmurings of the people of Israel; say to them, ‘At twilight you shall eat flesh, and in the morning you shall be filled with bread; then you shall know that I am the Lord your God.’”
In the evening quails came up and covered the camp; and in the morning dew lay round about the camp. And when the dew had gone up, there was on the face of the wilderness a fine, flake-like thing, fine as hoarfrost on the ground. When the people of Israel saw it, they said to one another, “What is it?” For they did not know what it was. And Moses said to them, “It is the bread which the Lord has given you to eat. This is what the Lord has commanded: ‘Gather of it, every man of you, as much as he can eat; you shall take an omer apiece, according to the number of the persons whom each of you has in his tent.’” And the people of Israel did so; they gathered, some more, some less. But when they measured it with an omer, he that gathered much had nothing over, and he that gathered little had no lack; each gathered according to what he could eat. And Moses said to them, “Let no man leave any of it till the morning.” But they did not listen to Moses; some left part of it till the morning, and it bred worms and became foul; and Moses was angry with them. Morning by morning they gathered it, each as much as he could eat; but when the sun grew hot, it melted.
–Exodus 16:10-21