The obligations of Purim — hearing Megillah, gifts to the poor, food to our friends and a festive meal — are rabbinic, and not Divine, decrees. The Purim story took place many years after Moses received the Torah.

Although the Torah authorises the leaders of each generation to make new laws, until Mordecai and Esther it was rarely done. Purim was the turning-point in the development of Judaism, from top down to bottom up, and that is what makes Purim of such significance.

When the Jews were exiled from the Land of Israel in 586 BCE, the entire framework for the Torah seemed to have collapsed. The laws given to Moses were designed to regulate a free people living in their own land, with cities, farms, the Temple in Jerusalem. All that had disappeared.

How could Judaism continue when it simply wasn’t designed for exile? By the time of Purim, many must have doubted whether it was possible.

That is why the Megillah opens with the description of the great party held by King Ahasuerus. Tradition tells us that at this banquet the vessels used in the Temple were repurposed for secular merry-making and that the Jews happily joined in.

Ahasuerus was trying to tell the Jewish exiles, “Your religion belongs in a land you don’t live in any more, in a Temple that does not exist anymore, and a time that is gone for ever. Just move on.” Many of the Jews of Shushan agreed with him. They turned up at the palace and put their past behind them.

The antidote to that attitude was provided by Mordecai and Esther. They realised that in order to ensure the continuity of Judaism, something had to be done; they had to act.

Mordecai is a perfect example of a religious activist. He not only refused to go to the party at the palace, he was also determined to pick a fight.

We will read in the third chapter of the Megillah: “All the king’s courtiers in the palace gate knelt and bowed low to Haman, for such was the king’s order concerning him; but Mordecai would not kneel or bow low.”

Ahasuerus created a new piece of court etiquette, that his servants should recognise Haman’s pre-eminence by bowing to him. There is nothing forbidden about that; the Talmud says that Mordecai refused to bow not because he was religiously obliged but as a protest against Haman’s arrogance and as a statement of Jewish pride.

Mordecai wanted to get into trouble. He wanted to do something to shake his fellow Jews out of their torpor. Just like when Rosa Parks refused to give up her seat for a white man on a bus in Montgomery Alabama in December 1955, it wasn’t because she was particularly tired that day.

Mordecai in his day, and Parks more recently, were not going to accept the status quo as inevitable or unchangeable, or as someone else’s responsibility to fix, they were going to take the initiative.

That is why Esther married the King, why she approached him though that placed her life in danger; why she invited her husband and Haman to not one but two intimate parties; why she so skilfully orchestrated the downfall of Haman. She and Mordecai realised that not everything will come from above.

We have to play our part too. In kabbalistic terms there are two ways for a spiritual impact to be exerted on the world: isarusa dil’eila, activity from above, and isarusa diltata, activity from below. What is more, the mystics teach that isarusa diltata prompts isarusa dil’eila; God responds to the activity we create by adding His own.

That is why it makes perfect sense that Purim was the beginning of modern Judaism, the moment when we, the Jewish people, started creating new laws and rituals for ourselves.

The abiding teaching of the Purim story is that solutions are found when we choose to act, when we don’t wait for others, or even the ultimate Other, to act first.

That remains true for our day. We have a responsibility to be innovative and creative. The religious and social landscape is totally different today than it was before Covid, let alone ten or 50 years ago.

The old ways do not work like they used to so new ways have to be found. There have to be attempts, failures, regroupings, rethinkings, until we develop the new methods we need to make Judaism — authentic, historic Judaism – succeed.

If we do that, if we engage in isarusa diltata, God will meet us halfway with isarusa dil’eila. That is what the story of Purim is about, that is what the laws of Purim at their root are about. We did it at the time of Purim and we succeeded. If we do it again, we will succeed again.

Rabbi Dr Elton is the chief minister of the Great Synagogue, Sydney, and one of the first group of Sacks Scholars newly selected by the Rabbi Sacks Legacy Trust