One of the central themes of Purim is קִיְּמוּ וְקִבְּלוּ – the people upheld and accepted the holiday. Chazal expound that this went beyond the context of the story – the people did not just embrace the holiday, but they embraced the Torah in a whole new way.
What happened on Purim that had never happened before?
The Sfas Emes teaches that what the people did on Purim, unprecedented, is that they unilaterally recognised that they needed to do teshuva.
What had never happened before was until then, there was always an external driving force, typically in the form of a prophet, warning the people to be better. In the face of obvious danger, they took responsibility for their futures, with the knowledge that when we become closer aligned to the way we ought to be, things get better for us. It’s a choice we can all make.
Until then, people just believed that things would turn out alright, with the exception of the really bad stuff, like idol worship, murder, and adultery. On Purim, the Jewish people recognised the spectrum – there’s plenty of other ways to fall short! In fact, the Megila opens with Jewish participation at a party celebrating their own downfall!
The story concludes with לַיְּהוּדִים, הָיְתָה אוֹרָה וְשִׂמְחָה, וְשָׂשֹׂן, וִיקָר – The Jews had light, gladness, joy and honour. אוֹרָה is understood to mean Torah, which feed into the novel interpretation of קִיְּמוּ וְקִבְּלוּ. But if אוֹרָה is Torah, why not just say Torah?
The Sfas Emes continues along the same vein. That for the first time, the people recognised the Torah as light, and tha Chagim are happy times. They could literally see the Torah in a new light!
At Sinai, there was no choice presented. Confronting and accepting the awesome reality of God, versus immediate doom is no choice at all. Prophets offering teshuva or doom is no choice at all.
Choosing it freely is massive. The heroes of the Megila do not act out of fear. They do not act in order to control outcomes. They just try their best, because being proactive is the right thing to do. And being proactive is a key motif of Purim, encompassing everything it celebrates.