Only don't rebel against Hashem. And you, do not fear the people of the land; for they are bread for us. Their protection is removed from over them, and Hashem is with us. Don't fear them."
The Ohr Hachaim notices that Yehoshua told Klal Yisroel that the Canaanim are ‘our bread’. Why did he choose this euphemism?
The Mekubalim write the reason that all living organisms need to eat and drink. Hashem could have made a world in which animals, or humans, could live without food or drink, yet He did not wish to. If we could live like that, our time would be free to serve Hashem and do His mitzvos all day, we would never have to work or chase money any more. Many of our misdeeds are based on our chasing money to eat, or the actual eating. By removing the need for food, we would save many problems.
The Ohr Hachaim suggests that so many of our mitzvos are based on eating, such as Teruma, maaser, challah, shemittah, and more. If we did not have to eat, we would not have so many mitzvos, and our efforts are worth our while to have so many opportunities to get close to Hashem.
However, the Mekubalim, including the Arizal (Sha’ar Hagilgulim 4) added another reason for the human need for food and sustenance.
All living creatures achieve a greater and higher level of sanctity by means of the food they consume. Sparks of holiness are trapped in each facet of creation, some more and some less, and they must be removed and sorted according to their level. When someone eats them and uses that sustenance purposefully, they separate the sparks of holiness from their unclean husks, elevating the sparks to their correct places. This concept applies even to the "unclean" creations; wicked people, and even Satan himself, all possess a certain degree of sanctity. In fact, the only reason a wicked person or Samael can continue to exist is this element of sanctity that he incorporates. As soon as this spark of holiness is lost, the item must cease to exist.
The Mekubalim also explain that the ability to attract a mate and pull other objects to itself is a product of this holy spark. It works as a magnet to pull to itself other things that will help it reach its correct purpose. The Gemara (Shabbos 34a) tells us that when Rabbi Shimon bar Yochai left his solitude in the cave, he saw the person who was responsible for his need to escape and hide. Rabbi Yehuda ben Geirim heard Rabbi Shimon bar Yochai expressing himself negatively about the Roman rulers and leaked the information that eventually reached the authorities who decreed that Rabbi Shimon shall be put to death. Rabbi Shimon turned his gaze toward Rabbi Yehuda ben Geirim and he turned into a heap of bones. Rabbi Yehuda was still alive before this meeting, which shows that he still had some spark of holiness inside him. Rabbi Shimon turned his gaze towards him and that spark was removed, now incorporated in Rabbi Shimon. Rabbi Yehuda immediately disintegrated, ceasing to exist.
The announcement of Yehoshua and Calev to Klal Yisroel was that the Canaanim were ready to become food for Klal Yisroel. By now, all Klal Yisroel had to do was to look at them. Their shadow had left them, meaning the spark of sanctity that kept them alive was already in the process of leaving them. Not only that, but וַה' אִתָנוּ - Hashem is with us. We, Klal Yisroel, do have the spark of holiness in us and we can pull the spark away from them through the law of attraction. There was nothing to fear from the Cana’anim, and they could be sure they would win any battle.
The Chasam Sofer adds to this concept based on the man that they used to eat. He writes that Chazal tell us that the man was a spiritual food, and it nourished Klal Yisroel on a spiritual level. The explanation to this is that the food grown in Eretz Yisroel has a greater spiritual capacity than other foods. When Klal Yisroel left Mitzrayim, their food came from Eretz Yisroel. Essentially, the holy sparks of the food from Eretz Yisroel were removed and transferred to the man that Klal Yisroel ate.
The possuk now reads כִּי לַחְמֵנוּ הֵם – for they are our bread. We have been eating their spiritual powers for the past year and a few months, סָר צִּלָם מֵעֲלֵיהֶם- their shadow, referring to the holy sparks, has abandoned them. Klal Yisroel had been eating their spiritual powers for some time, and they no longer had any powers.
