The Malbim says that the special Bracha of: בָּרוּךְ הַגֶּבֶּר אֲשֶּר יִבְטַח בַה' (Yirmiyahu 17:7), a person who has Bitachon in Hashem, was said when: וְהָּיָּה ה' מִבְטַחוֹ—his Bitachon is TOTALLY on Hashem; without any Hishtadlus, THEN he gets a Bracha. By Shemita, Hashem says not to work, i.e., no Hishtadlus, and then: וְצִוִּיתִי אֶּת בִרְ כָּתִי (Vayikra 25:21)—you get a Bracha. And probably, the less Hishtadlus, the bigger the Bracha. And by the holy Mitzva of Shemita we have a special: צִ יווּי (decree) of receiving Brachos (וְצִוִּיתִי).
We need to work on Menucha, which is a form of doing zero and letting Hashem run our lives. Even during Hishtadlus, do it with Menucha and be relaxed; this will bring much more Bracha.
Malbim on Yirmiyahu and Tehillim
The Malbim explains that only when a person trusts in Hashem without relying on natural means is he truly blessed. If one trusts in Hashem but expects salvation through natural means, then Hashem is not his true source of trust. True Bitachon is when Hashem is both the source and the means of salvation.
Kiddushin 20a and Tosafos
The Gemara teaches: כל הקונה עבד עברי כקונה אדון לעצמו—one who purchases a Jewish slave is as if he has acquired a master for himself. Tosafos explains that sometimes the master must give up his own comfort for the sake of the slave, illustrating the depth of the mitzvah to treat others with dignity and equality.
