The Torah commands in Parashat Mishpatim (Shemot 23:10), “Ve’shem Elohim Aherim Lo Tazkiru, Lo Yishama Al Picha” – “and you shall not mention the name of other deities; it shall not be heard upon your mouth.”
The Sefer Ha’hinuch brings three interpretations of this command.
The first is that this verse forbids swearing in the name of a foreign deity, and even causing a pagan to swear in the name of his god by demanding that he take an oath during a civil dispute. If a Jew claims that a pagan owes him money, and the pagan refuses, the Jew may not sue him, because he will then be causing the gentile to swear in the name of a pagan god.
Secondly, this command forbids conducting business with a pagan on or shortly before his religious holiday. If a gentile closes a lucrative deal before or on his holiday, he will express praise and thanksgiving to his deity, and the Jew will thus have caused him to speak in praise of his god. Therefore, it is forbidden by force of this command to engage in commercial dealings with pagans before or during their holiday.
Thirdly, this command forbids using an idol as a landmark. For example, one cannot tell his fellow, “Meet me at the corner, next to the idol.”
The Sefer Ha’hinuch explains that all this is forbidden because of the importance of distancing ourselves from anything associated with pagan worship. Idol worship is so detestable that the Torah does not want us even mentioning a pagan god’s name or even indirectly facilitating its worship. The Sefer Ha’hinuch adds that the Torah mentions the prohibition against idolatry forty-four times, in order to emphasize its singular severity and the need to firmly reject it and distance ourselves from it.
The Sefer Ha’hinuch, and the Rambam, maintain that this prohibition marks an exception to the standard rule that violators of prohibitions which are transgressed without performing an action are not liable to Malkut. One who takes an oath in the name of a foreign deity, according to the Rambam and Sefer Ha’hinuch, is liable to Malkut, even though this violation is committed verbally, and not by performing an action, due to the unique severity of idolatry.
This command, of course, applies to both men and women, both in Eretz Yisrael and outside the land, and at all times.
Already the Rishonim, approximately a thousand years ago, took note of the common practice among Ashkenazic Jews to permit conducting business with gentiles before and during their holidays. The Rishonim justified this practice by stating that this was allowed due to the concern of “Eba” – enmity that would be aroused by refusing to engage in commercial activities with the gentiles. If the Jews would suddenly discontinue trade and commerce with the gentiles during their holiday season, causing the gentiles financial losses, they will naturally resent the Jews, leading to hostility. Out of this concern, the Rabbis permitted doing business with the gentiles before and during their holidays.
Likewise, the custom developed to permit Jews to sue gentiles who owed them money, even though the gentiles would then swear in the name of their god. This was permitted due to the severe financial losses Jews would incur if there unable to bring gentiles to court.
These leniencies led Rav Moshe Feinstein (Russia-New York, 1895-1986) to the conclusion that these two prohibitions – conducting business with pagans during their holiday season, and demanding an oath from a pagan in court – were enacted by the Sages. In his Iggerot Moshe (Yoreh De’a, 1:71), Rav Moshe noted that if these were forbidden on the level of Torah law, they could not be allowed due to the concern of enmity or to avoid financial losses. Evidently, Torah law allows business with pagans during their holiday season, and demanding an oath from a gentile, and these prohibitions were enacted by the Rabbis.
Rav Feinstein explains this theory based on the principle of “Dabar She’eno Mitkaven,” which means that Torah law does not forbid an action which could result in an unintended violation. As long as the act is not committed with the intention to transgress a Torah law, and it is not certain that the act will have such a result, the act is allowed. When a Jew engages in commerce with a gentile during the gentile’s holiday season, he does not intend at all that the gentile will give thanks to his god, and this is clearly not certain to occur. Therefore, as far as Torah law is concerned, this is permissible, but the Sages enacted that this should be avoided in the interest of distancing ourselves from pagan worship. Likewise, when a Jew brings a gentile to court, he has no intention that the gentile would swear in the name of his pagan god, nor is this certain to happen. To the contrary, the Jew hopes that the gentile will simply admit to owing the money he claims in order to avoid falsely swearing. Therefore, Torah law does not forbid suing a pagan who will likely swear in the name of his god, but this was prohibited by the Rabbis.
Hence, as these prohibitions apply not on the level of Torah law, but rather by force of Rabbinic enactment, they are suspended when this will likely invite hostility, or when a substantial financial loss is at stake.
It should be noted, however, that the Sefer Ha’hinuch presents these three prohibitions – suing a pagan, conducting business with a pagan during a holiday season, and mentioning the name of an idol – as three interpretations of the verse “Ve’shem Elohim Aherim Lo Tazkiru.” This would certainly imply that in the Sefer Ha’hinuch’s view, all three are forbidden by the Torah. Rav Moshe, apparently, felt that common practice does not follow this view, and instead regards the first two as applying only by force of Rabbinic enactment, such that leniencies can be introduced when the need arises.