The Meor Einayim (Likutim כשרצה ה"ד) writes, "Whoever needs parnassah should read parashas haman every day, and he will receive Hashem's kindness from parashas haman."
Every Shabbos, for twenty-two years, Rebbe Menachem Mendel of Riminov zt'l would teach lessons from parashas haman to bring parnassah for Bnei Yisrael.
It is repeated in the name of Rebbe Menachem Mendel of Riminov zt'l that reading parashas haman on Tuesday of parashas Beshalach is mesugal for parnassah.
The Chidushei HaRim writes in a letter: "Rosh Chodesh Nisan, 5612: I thought of an idea: I should make a chiddush in parashas haman each day, and thereby my parnassah will come from the Torah. As the Midrash (Bereishis Rabba 97:3) states, יום בכל פרנסה, every day has its parnassah..."
Shulchan Aruch (Orach Chaim 1:5) states, טוב המן פרשת ...לאמר, "It is good to say...parashas haman." The Mishnah Berurah writes, "The Yerushalmi says that whoever says parashas haman every day is guaranteed that he won't ever lack parnassah."
The Tashbatz quotes this Yerushalmi and adds ערב ואני, "I guarantee it." לגלגלת עומר i(16:16) can be translated to mean that the parnassah comes לגלגלת from the emunah that is in a person's mind. When one says parashas haman, he strengthens his belief that Hashem gives him parnassah, and this emunah is mesugal for attaining parnassah.
It states (Yirmiyahu 7:28) ונכרתה האמונה אבדה מפיהם, meaning Hashem is complaining that the nation lost their emunah (האמונה אבדה). They don't even speak about emunah (מפיהם ונכרתה).
The Beis Avraham says that the pasuk is hinting, האמונה אבדה, if you lost your emunah, מפיהם ונכרתה, food isn't in your mouth. A person might lack parnassah, chalilah, because he lacks emunah.
There is a custom to give birds food on Shabbos Shirah. The Yismach Yisrael explains that when you feed an animal, such as your cow or horse, the animal feels it deserves the food because it works for you. But birds don't do anything for you. When they are fed, they understand that this is an underserved gift. We, too, seek to attain the awareness that Hashem doesn't owe us anything, and if we have parnassah, we should thank Hashem for His chesed.
