These sources accompany the Cross-Dressing on Purim episode of the Joy of Text podcast.
1. Rema, Shulhan Arukh, Orah Hayim 696:8
|רמ”א, שו”ע אורח חיים תרצ”ו:ח’
ומה שנהגו ללבוש פרצופים בפורים, וגבר לובש שמלת אשה ואשה כלי גבר, אין איסור בדבר מאחר שאין מכוונין אלא לשמחה בעלמא; וכן בלבישת כלאים דרבנן. וי”א דאסור, אבל המנהג כסברא הראשונה.
|As to the custom to wear masks on Purim, and a man wears a woman’s clothing and a woman a man’s clothing – there is no prohibition that is being transgressed in this case, since their only intent is for the sake of joy. The same is true in regards to wearing a Rabbinic form of shatnez. And some say that this is forbidden, but the practice is like the first opinion.|
2. Responsa Mari Mintz (Yehuda Eliezer Mintz, 1405-1508. Mainz and Italy), no. 15
|שו”ת מהר”י מינץ סימן טו
על דבר לבישת הפרצופים שנוהגין ללבוש בחורים וגם בתולות זקנים עם נערים בפורים.
נאם הטרוד יודא מינץ.
|Regarding wearing masks – as it is the practice for young men and women, young and old, to do so on Purim.
Behold, I have seen that a permissive ruling has already been given by my beloved friend… Rabbi Elyakim Sigal…
I have come to add my support to this, so that I will share a splinter of the beam (take some of the responsibility for this ruling), for it is a mitzvah to give a reason and to find a proof that will explain on what basis the greats of the generation, amongst whom I was raised, saw [and tacitly approved of] their sons and daughters, their sons-in-law and daughters-in-law wearing these masks and changing their clothes from men’s clothing to women’s clothing, and the reverse. And if there were – God-forbid! – even the slightest scintilla of a sin, the Heaven forfend that they would have been silent and not protested, and certainly regarding a Biblical negative prohibition (such as cross-dressing). Rather, they most certainly must have had a proof and basis that this was fully permissible, and that in such dressing up there is not even the slightest concern of a transgression…
And it seems to me that proof for their position can be brought from the braitta which is quoted in Avoda Zara…
From this we see that for those Tosafists, in a place where men and women have the practice to dress in the same way, there is no issue of “A man shall not wear a woman’s clothing”… And it is logical to say that because of the joy of Purim, everyone is the same in this leniency (i.e., since everyone is dressing up, on this day there is no sense of gender distinction regarding clothing).
Now since the other Tosafists justified a certain related practice on the principle that “God knows what is in our hearts,” and he also wrote that it is only forbidden (for a man to wear a woman’s clothing) when it is done as a way of beautifying oneself, and another Tosafot wrote that it is only forbidden when it is for the sake of beauty and adornment, as a woman would wear it, and only then does the prohibition of “A man shall not wear” apply – from this we can see that when done in a different way, it is permissible.
It also seems this way from Smag, Negative Prohibitions 60, regarding the prohibition of “A man shall not wear a woman’s clothing,” namely, that these prohibitions are dependent on a person’s intent. For we explain the verses according to the Tana who reads them according to their simple meaning, namely, that a man shall not wear clothing that is distinctive for a woman, like a veil or the like, in order to sit among women and for the purposes of licentious behavior (lit., adultery). And the same would be true for a woman wearing men’s clothing to sit among men… From this we see that Smag also is of the opinion that one does not transgress unless he is intending for licentious purposes… So we see that it is not forbidden unless one is wearing these garments to beautify himself…
(Signed) Yehuda Mintz.