"Then Moses said to them, 'No one is to keep any of it until morning.'" - Exodus 16:19
Have you ever seen God do something really good in your life only to find that you have abused the blessing He gave you? Such was the case of the Israelites as they were traveling through the desert on their way to the Promised Land. God was providing for them in miraculous ways. Manna was provided each day as their bread. God gave Moses specific instructions as to how this manna was to be eaten. God said each one was to gather only what he needed for that day. No one was to keep it until the next morning.
"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" (Ex. 16:20). God was teaching the Israelites daily trust in His provision for them. He wanted them to trust Him one day at a time. If they tried to hoard, God put a self-destruct feature in the manna. Yet God also told them to gather two days' worth on the sixth day so that they would have manna to eat on the seventh day. Interestingly, this manna did not stink or have maggots.
For many years I gathered manna in business out of fear of not having enough. One day, the Lord decided that manna should be destroyed in order for me to learn total trust in His provision. When we operate out of fear, we can expect the Lord to lovingly discipline us in order to help us learn to trust Him. There is a danger when we seek to "insure ourselves" against calamity. If your actions are born from fear, you can expect God to demonstrate His loving reproof so that you might not live in fear.