Exodus 16:17

When the dew that lay had gone, behold, on the surface of the wilderness was a small round thing, small as the frost on the ground.

When the children of Israel saw it, they said to one another, “What is it?” For they didn’t know what it was. Moses said to them, “It is the bread which the LORD has given you to eat.

This is the thing which the LORD has commanded: ‘Gather of it everyone according to his eating; an omer a head, according to the number of your persons, you shall take it, every man for those who are in his tent.’”

When they measured it with an omer, he who gathered much had nothing over, and he who gathered little had no lack. They each gathered according to his eating.

Moses said to them, “Let no one leave of it until the morning.”

Notwithstanding they didn’t listen to Moses, but some of them left of it until the morning, so it bred worms and became foul; and Moses was angry with them.