"Yet the Elohim does not give him power to eat of it"
The rabbis discuss how hard-hearted people are in that they pay no attention to the matters of the higher world. Rabbi Shimon says that one eats in this world the fruits that he merits, and the capital, his soul, is kept for him in the higher world so that he can gain with it the higher life above. But for whoever contaminates himself and does not deprive his soul or body of anything, the Tree of Life is not available for him to eat from. Rabbi Aba says that when Moses saw that the people complained about the manna he saw that this blemished his own perfection and he could not bear to see his own wretchedness. It was considered that descending from a higher to a lower level was like death.