The Torah in Parashat Ki-Teitzei (22:5) introduces the prohibition against cross dressing, forbidding a man from wearing women’s clothing, and vice-versa. The Sefer Ha-chinukh (542), based on the Rambam, offers two reasons for this prohibition, explaining firstly that it is intended to help prevent sexual immorality. Dressing like members of the opposite gender would likely result in excessive interaction and mingling with members of the opposite gender, which could then lead to forbidden relationships. This reason likely reflects the view among the Tanna’im cited by the Gemara in Masekhet Nazir (29) defining the prohibition as dressing like members of the opposite gender and then proceeding to inappropriately mingle with them. The Chinukh then adds that cross dressing was practiced by the ancient pagans, and the Torah therefore forbade such conduct as part of its effort to keep Am Yisrael away from pagan mores.
An additional perspective on this law may be gleaned from a Chassidic reading of this verse by Rav Yaakov Yosef of Polonne, in his Toldot Yaakov Yosef. He finds in this prohibition an allusion to the dangers of embracing a lifestyle and mode of conduct that is not appropriate for us at our current level. The Toldot Yaakov Yosef suggests that just as a man – a member of the gender which generally has greater physical strength – may not dress as a woman, and vice-versa, similarly, those with great spiritual “strength” should not act like those of lesser spiritual “strength,” and vice-versa. Each person, he explains, should act in a manner appropriate for those of his or her stature. People of distinction must conduct themselves with a special level of dignity, refinement and piety, and those of lesser spiritual stature should not endeavor to live at an especially high standard of piety which is unsuitable for them.
According to the Toldot Yaakov Yosef, this prohibition conveys a broader message that we must not try to become somebody who we aren’t meant to be. Certainly, we must constantly aspire to grow and become greater than we are, however, our immediate goals and ambitions must be appropriate for our current standing. Our objective should be achieving the most we can under our current conditions and circumstances, rather than “dress” ourselves in the “attire” of those whose conduct is not, at least yet, suitable for us. When the Torah forbids men from dressing as women, and vice-versa, the broader message conveyed is that we must be the best version of ourselves, rather than try to be somebody who we cannot be at this point. Personal growth must be incremental, undertaken through modest, reasonable changes on a step-by-step basis, and in accordance with our current capabilities. The Torah here warns us against “dressing” in “attire” that is not appropriate for us, trying to be somebody who we are not – at least yet – capable of being.