Exodus 16:18-20
18 And when they measured it by the omer, he who gathered much did not have too much, and he who gathered little did not have too little. Each one gathered as much as he needed.
19 Then Moses said to them, “No one is to keep any of it until morning.”
20 However, some of them paid no attention to Moses; they kept part of it until morning, but it was full of maggots and began to smell. So Moses was angry with them.