This second letter of Purim - Mordecai’s first letter Esther 9:20 was to some extent tentative, a recommendation. The Jews generally having accepted the recommendation Esther 9:23, Esther 9:27, he and Esther now wrote a second letter which was mandatory.
Related Commentaries of Esther 9:29
Esther 9:29
29 Then Esther the queen, the daughter of Abihail, and Mordecai the Jew, wrote with all authority,h to confirm this second letter of Purim.