The establishment of the Purim holiday marks a historic transition. A spontaneous celebration of survival and victory transforms into a binding, permanent tradition for all generations. This shift represents a partnership between the natural desire of the people to commemorate their miraculous rescue and the official authority of their spiritual leadership.
The acceptance of this new tradition involved the entire Jewish nation, yet it carried a profoundly unified character. The primary approach among commentators is that the people embraced the new obligation with one heart and deep joy, reminiscent of their unified acceptance at Mount Sinai. They acted together as a single body without any division [אור חדש, מנות הלוי, ישע אלהים, עמנואל הרומי, ביאור שטיינזלץ]. Conversely, this unified action can be understood as highlighting individual commitment, showing that every single Jew took the obligation upon themselves directly and personally [אבן עזרא, רלב״ג]. A unique perspective suggests that it was Mordecai himself who drove this acceptance, as his written correspondence ultimately inspired the people to adopt the formal tradition [מגילת סתרים].
The people's commitment evolved in two distinct stages: their initial, independent actions and the formal instructions they later received from Mordecai. One way to understand this progression is through time. The people naturally initiated celebrations in the immediate aftermath of the miracle during the first year, while Mordecai's letters established the formal obligation to continue observing these days annually for all future generations [אבן עזרא, עמנואל הרומי, מנות הלוי].
Another approach focuses on the specific practices of the holiday. The Jews naturally began to observe days of feasting and joy to express gratitude for their salvation. Mordecai, however, introduced new practices through his letters that they had not initially considered, specifically the sending of food portions to friends and giving gifts to the poor [רלב״ג, מנות הלוי]. While food is sent to peers who might return the favor, gifts to the poor represent an act of true kindness with no expectation of reward [מנות הלוי]. Additionally, Mordecai's writings instituted the formal obligation to read the scroll detailing the miraculous events [מנות הלוי].
A geographical distinction also explains the two stages of their acceptance. The residents of open, unwalled cities had already begun celebrating on the fourteenth day of the month of Adar on their own. Mordecai's letters were therefore directed at the inhabitants of walled cities, instructing them to celebrate on the fifteenth day, a practice they had not yet adopted [מלבי״ם].
The widespread agreement of the people stemmed from a combination of their natural urge to offer thanks for the miracle and their respect for Mordecai's authority as a prophet and a member of the Great Assembly [יוסף אבן יחיא]. Through his letters, Mordecai revealed the true severity of the original threat and the hidden Divine providence operating behind the lots cast by Haman. Grasping this deeper reality strengthened the people's resolve to permanently establish the holiday [מגילת סתרים, ישע אלהים]. Ultimately, this commitment extended to the entire Jewish nation in every location, even to those living outside the Persian empire, because of the unique spiritual light that is revealed during these days [נחל אשכול].