The foundational Tanach warning comes from Mishlei 30:8-9, where the author prays to be given neither poverty nor wealth, lest in satiation he renounce God saying "Who is the LORD?" — a recognition that excess material comfort poses a direct theological danger — and Tehillim 49:17-18 reinforces this by counseling not to fear when another grows rich, for at death nothing accompanies him, while Tehillim 62:11 warns explicitly against setting one's heart on accumulated wealth.
The Gemara Berakhot 32a makes the connection between material abundance and spiritual failure concrete: Moshe argues before God that it was precisely the lavish gold and silver poured upon Israel until they had enough that caused them to make the Golden Calf, compared to a cow fed rich lupines who then kicks its owner — excess prosperity breeds ingratitude and rebellion.
Pirkei Avot 2:7 states the rule in balanced, rhythmic form: more possessions bring more worry, while more Torah brings more life — a deliberate structural contrast — and Pirkei Avot 4:21 sharpens this into a warning that jealousy, desire, and the pursuit of honor remove a person from the world entirely, a statement codified and elaborated by the Rambam (Mishneh Torah, De'ot 3:1), who cites it verbatim before cautioning that the answer is not extreme asceticism but rather the middle path.
The Rambam (Mishneh Torah, De'ot 3:2) rules that a person must orient all his affairs — including commerce and earning wages — toward a single goal of knowing God, meaning that accumulating money cannot be an end in itself, and the Rambam (Mishneh Torah, De'ot 1:4) adds that the righteous person desires only what the body strictly requires, citing the verse "the righteous eats to satisfy his soul," with business exertion limited to what is needed for immediate life.
The Rambam (Mishneh Torah, De'ot 5:1) and the Rambam (Mishneh Torah, De'ot 5:10-11) together prescribe that a Torah scholar eats only what restores the body, avoids gluttony, and should always spend less than befits his income on himself — while the Rema in Shulchan Arukh, Yoreh De'ah 246:21 rules explicitly that one who thinks to engage in Torah while simultaneously acquiring wealth and honor will never merit the crown of Torah, and must instead minimize business, remove the pleasures of the time from his heart, and work only as much as he needs to sustain life.
The Chovot HaLevavot, Ninth Treatise on Abstinence 1-3 teaches that the Torah's entire aim is to make the intellect prevail over the soul's lusts, that the domination of desire over intellect is the beginning of all sin, and that people only turned toward worldly things after they had first turned away from Torah — the Yetzer Hara beautified worldly indulgence and self-aggrandizement until they were pulled under — while the Chovot HaLevavot, Fourth Treatise on Trust 3-4 identifies those who amass wealth purely for the honor it brings as profoundly foolish, because the honor the masses show to the wealthy is itself motivated by hope of personal gain from them.
רבינו בחיי, שולחן של ארבע שער ב teaches that it is not fitting for a person to pursue luxuries without end, for if one is already accustomed to eating and drinking from silver vessels, he will soon find even that insufficient and desire jeweled ones, and from one he will want two or three — a spiral without limit — and that the righteous person should eat only so that through bodily sustenance the soul can exercise its faculties in the service of God.
The Mesillat Yesharim, chapter 13 argues that all worldly matters are trials for a person, and that every worldly pleasure drags some sin in its wake — even food and drink, when permissible, lead through excess to the removal of the yoke of Heaven — while the Mesillat Yesharim, chapter 1 establishes the premise that man was created solely to delight in God and in the radiance of the Shekhinah, which is the only true delight, and the Mesillat Yesharim, chapter 26 concludes that the ideal of holiness means clinging to God so thoroughly that the physical objects a person uses are elevated by his use of them, rather than his attachment to them pulling him down.
Resisei Layla 35 warns that one who submerges himself in the constant pursuit of wealth, desires, power, and competition reaches a point where it becomes impossible for him to remember God at all — and this state of total immersion is compared to the Ten Tribes who assimilated so completely in Assyrian exile that they ceased to know they were Israel, illustrating that the pull of worldly preoccupation can extinguish Jewish identity itself.
The Tanya, Likkutei Amarim 7-8 teaches that any act, speech, or thought in worldly matters that is not performed for the sake of Heaven — even if entirely permissible — belongs to the domain of the animal soul derived from kelipah, while the Tanya, Likkutei Amarim 27-28 teaches that even in fully permitted pleasures, every time a person sacrifices his impulse — delaying a meal to study Torah, restraining speech — he subdues the sitra achra and performs an act of genuine spiritual significance, and מכתב מאליהו, חלק א עמוד יט observes that some people are given the specific trial of wealth and worldly pleasures, tested not to become so enmeshed in the material that they forget their Creator, echoing the very verse of Mishlei 30.
מכתב מאליהו, חלק ד עמוד יד teaches that when a wealthy person strives with all his capacity to use his possessions for the sake of Heaven and in accordance with God's will, Heaven then grants him new inner strengths to overcome the desire for acquisitions and to diminish their importance in his heart — suggesting that the spiritual danger of wealth is real but can be transformed through intention, while חכמה ומוסר, חלק ב ז קצז laments that material success amplifies desire for more and more business, whereas spiritual success should amplify longing for greater wisdom and virtue, and that the Torah took very seriously the loss of that spiritual appetite.
Igros Moshe YD 4:36 concludes, on our reading of the cited page, that premature abandonment of yeshiva study to pursue career preparation and livelihood — driven by anxiety about earning — constitutes the counsel of the wicked and is characterized as the Yetzer Hara's distraction, with Rav Moshe Feinstein strongly urging that young students remain in yeshiva and trust that wealth comes from God rather than from one's choice of profession.
