When one has bitachon, he knows Hashem can sustain him even if he works less. Therefore, with bitachon, one has more time to serve Hashem. This is the meaning of the pasuk טוב ועשה 'בה בטח, with bitachon, one has more time to do good.
The Be'er Mayim Chaim (Bereishis 58:5) writes, "The amount of money decreed for a person to earn on any given day will certainly occur. Even if he hides in a room within a room, the money will pursue him and reach him. The chacham (Sefer HaPninim, Shaar HaEmunah) writes, 'If a person runs away from his parnassah like someone running from death, his parnassah will run after him even quicker and catch up to him.' So, why should you work so hard, with all your strength, the entire day, from sunrise until sundown? Even if you work part of the day, you will certainly earn the same amount of parnassah as if you worked all day."
The Agra d'Kalah writes that this lesson is hinted at in the first pasuk of our parashah. He writes, "A person shouldn't say my strength and my many hishtadlus helped me. This would be serving avodah zarah with purity. Furthermore, his mind is constantly thinking about the foolishness of this world, considering how he can earn his parnassah and his needs. Whereas, when one trusts in Hashem, he is calm, and his thoughts are relaxed. He turns his mind away from thinking about the love of this world and its pleasures because he understands that his thoughts won't grant him more or less than what Hashem decreed.... The wise king (Shlomo HaMelech) said (Mishlei 19:21) איש בלב מחשבות רבות. This means a person is foolish, and he thinks many thoughts of hishtadlus, of how he can attain the love of this world, which is wealth and honor, but he won't get anything from these thoughts. He won't gain and he won't lose, rather, תקום היא 'ד ועצת, he will receive in accordance with Hashem's plan, and through the means that the Creator prepared for him."
"The Torah hints to this when it states ...אברם אל 'ה ויאמר, and ם"אבר is roshei teivos for יש'א לב'ב חשבות'מ בות'ר, people have many thoughts of how they can earn wealth. Hashem tells the person... מארצך לך לך, leave your ארציות, worldly temptations that you are attached to... Don't think about these matters because you won't gain anything from these thoughts... Rather, אשר הארץ אל אראך, whatever means of parnassah, I [Hashem] give you, do that, according to Torah."
אברם's name was changed to אברהם. A 'ה was added to his name. A 'ה, when written out in full, can be written in three ways: Either ,א"ה ,י"ה or ה"ה. The filler letters (called מילוי) spell א"הי. The Shlah HaKadosh (Shaar HaOsiyos 46 ,א) explains that it comes from the pasuk תקום היא 'ה עצת. The roshei teivos of א"הי are 'ה ירצה אם, "If Hashem wills it."
So, when a heh was added to Avraham's name, instead of איש בלב מחשבות רבות, which indicates the attitude of many who have many thoughts of how to earn parnassah, follow תקום א"הי 'ה עצת. Say א"הי, im yirtzeh Hashem, תקום, that will be your parnassah.
It states (Shemos 17:12) אֱמוּנָה יָד ָיו וַיְהִי. We know that emunah is in the heart, or in the mind. Why does the Torah say אֱמוּנָה יָד ָיו וַיְהִי that his emunah was in his hands? ברכה ישא of Modzhitz zy'a replies that the pasuk is discussing a person who works for his living. Even then, he must know that parnassah is from Hashem, and not the work of our hands.
The Gemara (Sanhedrin 92a) states, בו שיש מי כל מתעשר לסוף דעה, "Whoever has daas (intelligence) he will become wealthy in the end." The Maharsha explains that this means he has the intelligence to know that the parnassah comes from Hashem. This knowledge and emunah are mesugal for parnassah and wealth. The Maharsha says that we shouldn't explain the Gemara literally, that when one has דעה, intelligence, he will become wealthy, because it states (Koheles 9:11) לחם לחמים לא, some wise people are poor. So, it isn't דעה, intelligence, which is the root of someone's wealth. Instead, it is the דעה, belief and awareness that parnassah comes from Hashem. That awareness will result in wealth.
The Maharsha quotes the Gemara (Nidah 70b), "The community of Alexandria asked Reb Yehoshua ben Chinina, 'What can a person do to become wealthy?" Reb Yehoshua told them, באמונה ויתן וישא בסחורה ירבה. Literally, this means they should do a lot of business, and they should do business honestly. The people of Alexandria told them, "Many people tried that path, and they didn't become wealthy." Reb Yehoshau said, אלא שלו שהעושר ממי רחמים יבקש, "Rather they should daven to the One Whose wealth is His." He won't become wealthy from his work, but he can become wealthy from his tefillos, and from his awareness that everything is from Hashem.
It is explained (Noam Siach p.360) that, initially, Reb Yehoshua didn't tell them that the solution is tefillah, because he wanted to test them. He wanted to see whether they know that parnassah isn't from one's work, but from Hashem. Because if they think that they have the ability to become wealthy on their own, even if they daven, it won't be a perfect tefillah. Even after their tefillos, they will still be relying on their own strengths and abilities. Therefore, initially, he told them that the path to wealth is hard work. They responded that many do so, and they didn't become wealthy. Reb Yehoshua saw that they recognize that it isn't in the power of man to attain wealth on his own, so then he told them the proper counsel: pray to Hashem and recognize that parnassah comes from Hashem. These matters will result in wealth.
It states (Bereishis 3:19) לֶחֶם תֹּאכַל אַפ ֶּיךָ בְּזֵעַת. This is the curse that Adam received when he ate from the Tree of Knowledge that He will now have to work hard to earn his parnassah. Imrei Noam (Likutim 5) says that בְּזֵעַת is roshei teivos for תפילה זו בלב עבודה, the work of the heart, which is tefillah. This hints to us that one doesn't have to sweat (which is the literal translation of ַתבְּזֵע) to earn parnassah. Rather, he should sweat and invest strength in praying from the depths of his heart. That will give him parnassah.
Imrei Noam adds that although it states תעשה אשר בכל וברכתיך, that Hashem's brachos come from a person's work, prayer is also called work, as Chazal (Sanhedrin 65a) say, עקימת מעשה הוי שפתיים, the moving of the lips is called an action. Tefillah can be counted on as hishtadlus for parnassah. (This vort is also written in Maor v'Shemesh, Bishalach, quoting Reb Mordechai of Neshchiz zy"a.)
The Yismach Moshe (Bishalach) discusses the pasuk לֶחֶם תֹּאכַל אַפ ֶּיךָ בְּזֵעַת, "With the sweat of your face you will eat bread." He explains that there are two translations of לֶחֶם. One is bread, the other is Torah, as it states (Mishlei 9:5) בלחמי לחמו לכו. Mankind was cursed that they must sweat and work hard to earn their parnassah. But instead of working hard to earn לֶחֶם, bread, one can work hard to earn the other translation of לחם, which is Torah. And when one toils in Torah, he will also have parnassah in abundance, and he won't need to work hard for his parnassah.
