The Torah portion dealing with the heavenly food that Hashem provided daily for the Jews in the desert over 40 years includes instructions on how they were to deal with this miracle.  The people were commanded to collect what they needed for that day and no more.  They were expected to trust that Hashem will provide again tomorrow to give like He gave today.  This trust in Hashem is called bitahon. The Maharal from Prague said that one who trusts in Hashem does not ask "What will I eat tomorrow?" In Hovot haLevavot it says that one who knows his father cares about him need not worry about anything.  King David compared himself to a baby nursing from his mother, trusting always - with no need to worry because she would take care of all.

 To drive this point home, Hashem instructed Moshe to tell the people that they should not leave over any of the food they collected to the next morning.  In fact, if someone violated the command their food spoiled and rottted and gave off a horrible stench.

 In 1939, after the Nazis invaded Poland Rabbi Soloveithcik zt’l and his oldest son were in Warsaw.  Air raids plagued the city on a daily basis forcing everyone into hiding.  A kind member of the community who realized the Rabbi was in their midst, brought him some bread each and every day.  The Rabbi and his son made a point to finish eating all that they had each day to demonstrate their trust in God and to show that they were not worried about tomorrow.  The only day they left any food over was on the eighth day of the Jewish month Tishre. 
"Tomorrow my son," said the Rabbi, "it is a misvah to eat extra food in preparation for the holy day of Yom Kippur and the fast that it entails.  We should save some food from today to be sure we will be able to fulfill Hashem's commandment tomorrow."

 The next morning when their benefactor arrived he brought them two loaves of bread as he always did. 
 "Excuse me Rabbi," he said, "I had prepared for you a special dish of cooked fish today but during the bombing some debris got in the bowl and spoiled the contents."
"I see from this incident," said the Rabbi, "that we should have trusted in God even today to provide the extra that we would have needed to fulfill his commandment."

In the Torah portion that speaks about Heavenly Manna, Hashem told Moshe "let the people go out and take each day's portion on that day, so that I can test them whether they will follow my teachings or not" Hashem has put man in a world of nature which conceals His control from human eyes.  Man is expected to see beyond the natural and acknowledge the power of Hashem that controls everything.  The lesson of the Manna is to see beyond nature and acknowledge that Hashem is the one who produces all that we need.  May we pass that test and prompt Him to give us bounty and blessing.

Shabbat shalom.