Exodus 16:13-15

That evening quail came and covered the camp, and in the morning there was a layer of dew around the camp. When the dew was gone, thin flakes like frost on the ground appeared on the desert floor. When the Israelites saw it, they said to each other, “What is it?” For they did not know what it was. Moses said to them, “It is the bread the LORD has given you to eat.