Eruvin 69B

עד דהוי מומר לעבודה זרה.

unless he is an apostate with regard to idolatry. As long as he has not worshipped idols, his transgression of a single prohibition does not put him under suspicion of transgressing the rest of the Torah.

אמר רב נחמן בר יצחק: ליתן רשות ולבטל רשות. וכדתניא: ישראל מומר, משמר שבתו בשוק ⁠— מבטל רשות, שאינו משמר שבתו בשוק ⁠— אינו מבטל רשות.

Rav Naḥman bar Yitzḥak said: Rav Huna was not attempting to offer a broad definition of an apostate, but was rather referring to the specific issue of giving away rights or renouncing rights in a domain with regard to the halakhot of eiruvin. And as it was taught in the following Tosefta: An apostate Jew, if he observes his Shabbat in the marketplace, i.e., in public, he may renounce his rights in a domain like a regular Jew, but if he does not observe his Shabbat in the marketplace, he may not renounce his rights in a domain, as he is no longer considered a Jew in this regard.

מפני שאמרו: ישראל נוטל רשות ונותן רשות. ובגוי, עד שישכיר. כיצד? אומר לו: רשותי קנויה לך, רשותי מבוטלת לך ⁠— קנה, ואין צריך לזכות.

This distinction is significant due to the fact that the rabbis said: A Jew may receive rights and give away rights in a domain through a mere statement of renunciation, but with regard to a non-Jew it is not so, as he may not transfer his rights to others or renounce them in a domain unless he actually rents it out. How so? A Jew may say to his fellow: May my rights in this domain be acquired by you, or May my rights in this domain be renounced to you, and his fellow thereby acquires those rights, and it is not necessary that he take possession of it through a formal mode of acquisition.