Michtav M’Eliyahu (01 page 197) It has already been explained that all man's efforts in earning a living is so that he may learn about Divine providence and withstanding tests. Also to know , that there is no such thing as Nature at all, but everything is from G-d alone. That is why the need to engage in a job varies according to the degree the man is aware of G-d’s providence.
Michtav M’Eliyahu (01 page 197) There are five different levels concerning the awareness of G-d’s providence. The highest level is the man who has already stood the test, and recognized that the miracle and nature are both truly visible miracles, and knows that there is no real nature. , For such a person there is no longer a need for the test of "by the sweat of your brow you shall eat bread". And it is proper for him to rely all the time on his attachment to G-d and His Torah, since there is no reason to conceal the miraculous from him. This is the method of R. Shimon bar Yochai, that as long as Israel does the Will of G-d. their work is done by others...
Michtav M’Eliyahu (01 page 197) The second level concerning the awareness of G-d’s providence: There are no miracles from heaven except for those who have reached the perfection of bitachon. They view miraculous and the natural in their hearts as being totally identical. Thus they perceive that nature does not exis and that is simply a test. But for those who have not yet reached such perfection, they should behave as if Nature exists and is real. He needs to overcome natural challenges. He still is required to obey the curse of with the sweat of your breath you shall eat bread, this is the level that Rabbi Ishmael prescribes in the dispute with Rabbi Shimon. If such a person refuses to work and insists on relying on miracles, he will not be successful.
Michtav M’Eliyahu (01 page 197) The third degree concerning the awareness of G-d’s providence, is the one who sees nature merely as a tool in G-d’s hand. and he does not see that nature is not real. Also there exists varying degrees of these levels. Someone who has reached the degree of R. Ishmael should have a job, because in every act he continues to find out for himself the nonreality of his deeds. Thus for such a person working actually increases his spiritual level. But he who is at a lower level than this, there is the fear that his actions will not add clarity to his knowledge, but will actually cause him to descend and to think that Nature is real. For such a person nature activities are dangerous and he should minimize them as much as possible.