Moshe commanded the Children of Israel not to leave over any manna for the next day.  Anyone who defied this command found that the leftover manna was infested with worms for no apparent reason.  No matter how well they tried to preserve it, it somehow spoiled.  The purpose of Hashem orchestrating events in this manner was to teach the Children of Israel that they have absolutely no ability to prolong their wealth.  Today’s wealth differs from yesterdays and from tomorrows.  Whoever tried to hoard more than the daily portion saw no blessing from those superfluous efforts. ~ The Garden of Riches