The Shulhan Aruch (Orah Haim 156), after presenting the laws of prayer and the requirement to set aside time for Torah study, emphasizes the importance of earning an adequate livelihood (listen to audio recording for precise citation). He writes that if one studies Torah without working to earn a living, he runs the risk of falling into poverty, a situation that could prevent him from learning altogether. It is therefore imperative that a person find a means of supporting himself.

The Be'ur Halacha (section of the Mishna Berura commentary by Rabbi Yisrael Meir Kagan, 1839-1933) notes, however, that one who wishes to devote himself exclusively to Torah learning may absolve himself of the burden of earning a livelihood and rely on God to support him. Based on a comment of the Rambam (Rabbi Moshe Maimonides, Spain-Egypt, 1135-1204), the Be'ur Halacha writes that just as God supported the tribe of Levi, which did not engage in agriculture and devoted itself to Torah, similarly, people who are uniquely suited for full-time learning may rely on the Almighty for their sustenance. The ruling of the Shulhan Aruch is thus intended for the majority of people, who are entitled and indeed required to find a suitable and sufficient means of sustenance.

The Shulhan Aruch then adds that one must ensure not to make his profession the "Ikar" – the primary aspect of his life. Rather, Torah must constitute his primary occupation, and his work should be relegated to secondary status. The Mishna Berura (listen to audio recording for precise citation) explains this to mean that one should work only as needed for his livelihood, and not beyond that level. He adds that in determining his necessities, a person must avoid the lures of the evil inclination, which often misleads a person into mistaking luxuries for necessities. A person should very carefully and honestly assess what his needs are, and work only to meet those needs, so that he has time for intensive Torah learning.

In this context the Shulhan Aruch also warns of the importance of conducting one's business affairs "Be'emuna" – honestly. It is strictly forbidden to cheat, lie or mislead for profitable gain, or to charge interest on loans given to a fellow Jew. In short, one must ensure to comply with all the rules governing financial relations presented in the Hoshen Mishpat section of the Shulhan Aruch.

The Shulhan Aruch's formulation of this Halacha is taken from a famous passage in Masechet Shabbat (31), where the Gemara tells that one of the three questions one will be asked when he stands in judgment is, "Nasata Ve'natata Be'emuna?" Literally, this means, "Did you conduct business honestly?" Rav Shimon Schwab (1908-1993), however, suggested that the word "Emuna" in this passage might also be interpreted to mean "faith," meaning, faith in the Almighty's ability to provide. The Gemara admonishes us to conduct our professional affairs with a keen awareness of the fact that ultimately, it is God who provides a person's livelihood, and not his own efforts and initiative. Although a person must exert the effort, he must realize that the success of those efforts depends on the Almighty. This realization will lead a person to work only as necessary for a living, rather than working all day and night. Once he understands that God is the true Provider, he will work only to fulfill his obligation to exert effort, and spend the rest of the time engaged in Torah study. Furthermore, this outlook will prevent a person from resorting to dishonest means of earning money. If he acknowledges that his livelihood ultimately depends on the Almighty, he will naturally ensure to work only in accordance with God's laws, and not try to earn money illegally.

Thus, one must ensure to conduct himself in the marketplace "Be'emuna" – with faith in God, which will naturally result in the limiting of one's professional engagement, and his strict adherence to the laws of business ethics.

It should be noted in this context that we find in this Siman of the Shulhan Aruch (156) one of the longest passages in the entire Mishna Berura (Se'if Katan 3). In this passage, the Mishna Berura lists the many Misvot that a person can fulfill each and every day of his life. It is worthwhile for one to read through this passage to learn of the many opportunities that present themselves each day to fulfill Misvot, even while simply going about his normal routine.