8 Moses said, “This will happen when the LORD gives you meat to eat in the evening, and bread to the full in the morning; for the LORD hears your grumblings which you grumble against Him. And what are we? Your grumblings are not against us but against the LORD.”
9 Then Moses said to Aaron, “Say to all the congregation of the sons of Israel, `Come near before the LORD, for He has heard your grumblings.'” 10 It came about as Aaron spoke to the whole congregation of the sons of Israel, that they looked toward the wilderness, and behold, the glory of the LORD appeared in the cloud. 11 And the LORD spoke to Moses, saying, 12 “I have heard the grumblings of the sons of Israel; speak to them, saying, `At twilight you shall eat meat, and in the morning you shall be filled with bread; and you shall know that I am the LORD your God.'”
13 So it came about at evening that the quails came up and covered the camp, and in the morning there was a layer of dew around the camp. 14 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. 15 When the sons 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 which the LORD has given you to eat. 16 “This is what the LORD has commanded, `Gather of it every man as much as he should eat; you shall take an omer apiece according to the number of persons each of you has in his tent.'” 17The sons of Israel did so, and some gathered much and some little. 18 When they measured it with an omer, he who had gathered much had no excess, and he who had gathered little had no lack; every man gathered as much as he should eat. 19 Moses said to them, “Let no man leave any of it until morning.” 20 But they did not listen to Moses, and some left part of it until morning, and it bred worms and became foul; and Moses was angry with them. 21 They gathered it morning by morning, every man as much as he should eat; but when the sun grew hot, it would melt.
It amazes me that, no matter how clear the instructions are, someone will always not follow them. Most of the Israelites did what they were told. They left nothing of the manna until morning. A few were stubborn, and did not trust God to provide the next day. They received a lovely surprise when they woke up the next morning. When God asks you to do something, there’s always a reason. Don’t try to take matters into your own hands, or you might end up with a smelly wormy mess.