Exodus 16:14; Exodus 16:15

14 And when the dew had gone up, there was on the face of the wilderness a fine, flake-like thing, fine as frost on the ground.

15 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 that the LORD has given you to eat.