The culmination of the miraculous rescue involves a transition from a spontaneous celebration of gratitude into a permanent law for all generations. Establishing the holiday required a blend of spiritual and political authority, and recording the events in writing gave them eternal validity. The emphasis on Esther's specific command in cementing the holiday raises a question about her unique role. The primary approach among commentators is that Esther, as queen, held the royal authority necessary to compel the people to accept the decree, whereas Mordecai was a private citizen with limited power [אור חדש, ביאור שטיינזלץ, עמנואל הרומי, רלב״ג].
Others explain that her command refers to her persistent pleas and arguments to the sages of that generation, whom she ultimately convinced to establish the holiday as an everlasting law [רש״י, מלבי״ם]. Another perspective notes that she merely spoke the words but did not actually sign her name to the official letter, unlike Mordecai [אבן עזרא מהדורא תניינא]. A different conceptual approach links her statement back to the moment she informed the king of the assassination plot in Mordecai's name. The very act of repeating something in the name of its original speaker brought redemption to the world and formed the foundation of the miracle [ישע אלהים]. Even though she did this against Mordecai's wishes at the time, her action ultimately led to salvation [חומת אנך].
The establishment of the holiday is also closely tied to the earlier decrees regarding fasting. Although Mordecai and the high court decreed the fasts, it was exclusively Esther's command that cemented the actual holiday for all generations, as the original three-day fast was never meant to be a permanent fixture [תורה תמימה]. Still, some emphasize that the holiday is only truly complete through the combination of both elements: the fasts instituted by Mordecai and the royal command of the queen [אור חדש, ישע אלהים].
Recording the events in a book signifies the transformation of the scroll into a permanent part of the holy scriptures. Esther requested that the sages write down the story and add it to the biblical canon. After some initial hesitation and debate, they agreed, having found a supporting hint in the Torah [רש״י, מלבי״ם, נחל אשכול, יוסף אבן יחיא]. Writing the scroll was intended to preserve the hidden secrets of redemption contained within it, providing the Israelites with hope and trust in God throughout their years in exile [ישע אלהים].
From a practical standpoint, referring to the text as a book carries legal weight regarding how it must be prepared, requiring the scroll to be sewn together with animal sinews just like a Torah scroll [תורה תמימה]. Historically, there is a debate regarding the specific identity of this text. Some maintain that it refers to a known, specific historical record from that era, such as the royal chronicles, which has been lost to time [אבן עזרא, עמנואל הרומי]. Conversely, others state simply that it refers to the scroll itself, the very text read every year [אבן עזרא מהדורא תניינא, ביאור שטיינזלץ].