Parshas Vayeishev: The Danger of Rationalizing Sin as Lishem Shamayim

Rabbi Zweig addresses a question that troubled him for many years regarding two seemingly contradictory statements by Rashi (רש"י) in Parshas Vayeishev. When Yaakov sees Yosef's bloodied coat and declares "tayvah ra'ah achalashu," Rashi explains this as a nevuah referring to Aishes Potifar's future attempted seduction. Later, Rashi explains that the Torah (תורה) juxtaposes the story of Yehuda and Tamar with Aishes Potifar to teach "mah Tamar lishmah, af Aishes Potifar lishmah"—just as Tamar acted for the sake of Heaven, so too did Aishes Potifar. Yet the Torah clearly presents Aishes Potifar's actions as sinful. How can she be both a chayeves (sinner) and acting lishem Shamayim? The resolution lies in understanding what "lishem Shamayim" means in Aishes Potifar's case. She saw through astrology that she would have descendants from Yosef (though she didn't know it would be through her daughter). Because she desired Yosef, she rationalized her lust as a righteous act—she convinced herself she was acting for the sake of Heaven. This self-deception doesn't absolve her; it actually makes her sin worse. When someone knows they're doing wrong, they can do teshuvah and stop themselves. But when someone deludes themselves into believing their sin is a mitzvah (מצוה), they become completely unrestrained.