When not to follow your Rebbe

Rashi (vayikra 26:1) explains the strange way the Torah ends parshas Behar. Given that it just discussed a Jew who is a servant to a nonjew, he may think that since his Rebbe (master) did avoda zara, Chillul Shabbos, and gilui arayos, so can he. The Torah is reminding him that he cannot. Q: Why would I think he could??? This episode takes up this question and reveals an important point about our keeping the mitzvos (even if we aren’t servants of nonjews).