This mandate requires avoiding any kind of dishonesty, certainly financial dishonesty. Finally, there is the issue of chillul Hashem. In fact, theft from a gentile is actually worse than theft from a Jew because it causes a chillul Hashem. Similarly, according to Tosafot, there is no dispute that robbing from a gentile is prohibited where it will cause a chillul Hashem. 12 Halachically speaking, there is no question about the permissibility of the evasion of taxes.
Tax evasion is both a sin and a crime.
It violates numerous biblical prohibitions, including that of chillul Hashem. In addition to active tax evasion, Halacha prohibits enabling others to commit the transgression. These rules unquestionably apply in the United States and most Western countries, where the tax system is administered in an even-handed and objective fashion. If one would not patronize a restaurant owned by a religious Jew who serves non-kosher food, then one should not patronize a store owned by a religious Jew who cheats on his taxes. Even paying cash for an item is forbidden where circumstances suggest that the purchase will not be reported to the appropriate tax authorities.