Halakhah for Eruvin 6:1
הַדָּר עִם הַנָּכְרִי בֶחָצֵר, אוֹ עִם מִי שֶׁאֵינוֹ מוֹדֶה בָעֵרוּב, הֲרֵי זֶה אוֹסֵר עָלָיו, דִּבְרֵי רַבִּי מֵאִיר. רַבִּי אֱלִיעֶזֶר בֶּן יַעֲקֹב אוֹמֵר, לְעוֹלָם אֵינוֹ אוֹסֵר עַד שֶׁיְּהוּ שְׁנֵי יִשְׂרְאֵלִים אוֹסְרִין זֶה עַל זֶה:
If one dwells in a courtyard with a gentile or with one who does not acknowledge (the institution of) eruv, [i.e., a Cuthite], he (the latter) forbids him (the Israelite) [from carrying from his house to the courtyard until he rents from him his rights in the courtyard.] These are the words of R. Meir. R. Eliezer b. Yaakov says: Only two Israelites can forbid it, one to the other. [Both according to the first tanna and according to R. Eliezer b. Yaakov the dwelling of a gentile is not called a dwelling and, by law, he does not forbid; but the rabbis decreed (that he does forbid) so that an Israelite not come to dwell with an idolator and not learn from his deeds. The first tanna holds that even though a gentile is suspect of bloodshed and a Jew is forbidden to be alone with him, it sometimes happens that an Israelite dwells together with an idolator, and the rabbis ordained that an eruv not avail with a gentile and that negation of his (the gentile's) rights (in the courtyard) not avail, but that he must rent it (to the Jew). And the gentile will not rent it, fearing witchcraft. As a result, a Jew will not come to dwell with a gentile and he will not learn from his deeds. And R. Eliezer b. Yaakov holds that since an idolator is suspect of bloodshed — for two (or more Jews), who might dwell with a gentile, the rabbis made this decree; for one, for whom it would be uncommon to dwell with a gentile, it being forbidden to be alone with him, they did not decree. The halachah is in accordance with R. Eliezer b. Yaakov. And it (the courtyard) is rented from an idolator even for less than a p'rutah, and even on Shabbath. And even though a gentile cannot (merely) negate his rights, but must rent (his courtyard) to the Jew, a Jew can negate his rights even on Shabbath. That, by telling his neighbor, when an eruv has not been made: "My rights are ceded to you." In this event, he is forbidden to carry in the courtyard and his neighbor is permitted to do so. And if they so desire, after the one has carried therein what he needed to, he can cede his rights to the other, in which instance it becomes permitted to the other and forbidden to him.]