Exodus 16:13-15

So it was that quails came up at evening and covered the camp, and in the morning the dew lay all around the camp. And when the layer of dew lifted, there, on the surface of the wilderness, was a small round substance, as fine as frost on the ground. So when the children 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, “This is the bread which the LORD has given you to eat.