Exodus 16:4, 14

Then the LORD said to 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 test them, whether or not they will walk in My instruction.

When the layer of dew evaporated, behold, on the surface of the wilderness there was a fine flake-like thing, fine as the frost on the ground.