DEUT291 "You must not test Hashem, your God" [this verse]. We have herein been admonished that a person should not say, "Let me test through charitable work [this does not include giving ten percent of one's gain to charity, where one is allowed to test Hashem; see below] whether Hashem will make me successful" or "Let me determine through proper deeds whether He will enrich me with silver and gold." A good person [I.e., Whose only desire is to fulfill the will of Hashem (Sha'arei Teshuvah Hamevo'ar)] will not weaken [in his service of Hashem, even] if, after having labored with wisdom, knowledge, and proper deeds [I.e., Following the way of Hashem (Sha'arei Teshuvah Hameforash)] he still has not been successful in acquiring wealth or any of the other physical benefits [of life]. Our Sages, z"l, said (Ta'anis 9a) that only concerning the mitzvah of tithes is it permissible to test Hashem, as the pasuk says (Malachi 3:10), "Bring all the tithes to the store house, that there may be food in My house, and test me now with this." [Rabbeinu Yonah in his Sefer HaYir'ah expands this dispensation to include tithing all one's gainful wealth, and does not limit it only to the tithing of produce (ma'asros).