Not to overdue the effort of Parnasa:[1]

One should not increase in work and business more than necessary for his desired income. In the words of the Tzemach Tzedek[2] “However, every individual who does not desire to be rich but simply desires to make enough money to support himself and his household does not need to increase in business so much, but rather just the amount necessary to make enough money to support his family…..Every individual who fears for his soul and does not want to diminish the supernal kindness that was determined for him on Yom Kippur to draw all of it down into money, and it is not pressing for him to be wealthy, but rather simply to support his soul and his household with food, clothing, and a house so he can serve G-d, then he should estimate how much money he needs for these expenses and request mercy from G-d that G-d send him His supernal kindness and then he should work a job or business that can make this amount of money. For example, if he needs to make 500 rubles, then he should prepare a business that can make him this amount of profit. One should not increase in business more than necessary, as why should he make a larger garment than is necessary for the amount of divine energy of Parnasa he desires it to contain, as it is not the garment that draws the profit, but the blessing of G-d, and this blessing can be contained within a much smaller garment. On the contrary, one who increases in business is doing damage, similar to one who sews a garment that is longer than necessary for his body, which will cause him to trip and fall.”

Not to compromise on religious duties due to work: Being that one is required to work in order to make for himself a living, and support himself and his family, stated above, it is very easy for the evil inclination to challenge a person to overdue his efforts on expense of Torah learning and praying with a Minyan.[3] Although in a time of necessity, one may work on expense of Davening with a Minyan, this only applies in a case of true necessity, and even then one who has strong enough trust in G-d should trust in Him to find him a job that will not require him to compromise on praying with a Minyan.[4] To quote from Hayom Yom[5], “No matter how much effort is exerted, no-one can earn one cent more than G-d has ordained that he – this particular person – shall earn. One must do what is necessary, but one must remember that all his work is but a vessel. The main thing is G-d’s blessing, and that blessing is earned by being observant of G-d’s commands: Davening with a minyan, observing Shabbat b’hidur (beyond the minimum, with “beauty”), meticulous observance of kashrut, having Kosher Milamdim for ones children.”

Summary:

One is required to place his absolute trust in G-d, that G-d will provide him with a Parnasa to support himself and his household. Together with this trust, one is required to also place effort to make a living and hence is to work for at least part of the day, depending on how much money he wants to make, and on his level of Bitachon. Nonetheless, at the very least one’s efforts may not override the following, and he must have at least a minimum of Bitachon that not compromising on the below will not affect his sustenance:[6]

1. Davening with a Minyan [unless time of great need, depending on level of Bitachon]
2. Kevius Itim Latorah by both day and night, preferably immediately after Shacharis.
3. Not transgressing any matter of business law [i.e. Ribis, stealing, cheating, lying, dishonesty, Hasagas Gevul, etc].
4. Giving Tzedaka

[1] See Likkutei Torah Parshas Ki Seitzei p. 37c; Derech Mitzvosecha Mitzvas Tiglachas Metzora pp. 213-214; Kuntrus Umaayan

[2] Derech Mitzvosecha Mitzvas Tiglachas Metzora pp. 213-214

[3] See Chofetz Chaim Pesichas Asei 12

[4] See Igros Kodesh 3:372

[5] Hayom Yom 16^th Adar Sheiyni

[6] See Bitachon Vihistadlus Perek 9