In Sefer M’Zekeinim Esbonen, Rav Yisroel Shimon Kastelanitz zt”l brings the following letter that he wrote to a grandson who was struggling with parnassah:
“What can I tell you? I too have known this bitter taste for many years. I know how much it affects the heart. I can only write a few things that may calm your mind, and pray that Hashem sends His salvation.
“Sefer Pri Ha’aretz (Michtav 21) writes that parnassah is withheld when one relies on a ‘factor’ – for example, if one relies on his strength or intellect or business acumen to provide his livelihood. The Chovos Halevavos (Shaar Habitachon) and Mesilas Yesharim also write that anyone could sit idly and receive parnassah if not for the curse of ‘by the sweat of your brow you shall eat bread.’ One can fulfill this decree with just a little hishtadlus. It is said that a fool believes that this decree – that one must sweat to earn a living - is a mitzvas asei and he hasn’t sweated enough yet to fulfill it.”
