The Gemara towards the end of Masekhet Ta’anit (29a) introduces the famous halakha of “mi-she’nikhnas Adar marbin be-simcha” – that we increase our joy when the month of Adar begins. This halakha was stated by Rav Yehuda bar Rav Shemuel bar Sheilat, who cited it in the name of Rav.
Numerous writers (including Rav Moshe Wolfson in Emunat Itekha, vol. 1, p. 293; and Rav Petachya Menken in Pardes Petachya, Parashat Beshalach) noted the significance of the fact that this halakha was conveyed specifically by Rav Yehuda bar Rav Shemuel bar Sheilat. The Gemara in Masekhet Sanhedrin (96b) and Masekhet Gittin (57b) famously tells that Haman had descendants, or a descendant, who taught Torah in the city of Bnei-Brak. The Ein Yaakov cites the Gemara’s comment with an additional phrase, identifying this descendant as Rav Shemuel bar Sheilat. Indeed, the Gemara elsewhere (Bava Batra 8b) tells about Rav Shemuel bar Sheilat’s exceptional and selfless commitment to the schoolchildren whom he taught. Interestingly enough, Rav Shemuel’s son – Rav Yehuda – is the one whom the Gemara cites as introducing the halakha of “mi-she’nikhnas Adar marbin be-simcha.” It was a descendant of Haman, of all people, who conveyed to us the requirement to rejoice with the onset of the month of Adar.
If so, then Rav Yehuda’s ruling is another expression of the “reversal” theme that features prominently in the Purim story. The Megilla (9:1) describes how the situation in the Persian Empire was reversed as the Jews dominated their foes, as opposed to the original plan, which was for their enemies to dominate them. Later (9:22), the Megilla speaks of the month of Adar being transformed from a month of calamity to a month of jubilation. In Rav Yehuda bar Rav Shemuel’s halakhic ruling, we encounter the transformation of Haman himself, in a certain sense, as he had planned Adar to be the month of the Jews’ annihilation, and ultimately his descendant introduces the obligation to rejoice during this month.
Additionally, the ironic emergence of a Torah scholar from Haman demonstrates that ultimately, everything is good. Chazal famously instruct, “A person is obligated to become inebriated on Purim until he cannot distinguish between ‘cursed is Haman’ and ‘blessed is Mordekhai’” (Megila 7b). The message underlying this seemingly peculiar statement is that on Purim we recognize the “Mordechai” within every “Haman,” the blessing within every curse. Although we must confront and struggle against evil in all its various forms, Purim reminds us that ultimately, everything is for the best. The story of Purim itself conveys the message that even the darkest and gloomiest circumstance is eventually shown to be something positive. Somewhere behind the mask of evil and suffering there is goodness, though it may take many generations for us to identify it. Rav Shemuel bar Sheilat came along many centuries after Haman and revealed the good latent even within this evil family. Appropriately, his son announces to us the message of the special of joy of Purim, the joy of knowing that whether or not we can see how, all that happens is ultimately for the best.