Esther 8:8 (ESV)

8 But you may write as you please with regard to the Jews, in the name of the king, and seal it with the king’s ring, for an edict written in the name of the king and sealed with the king’s ring cannot be revoked.”

Esther’s request would not have surprised the king. At the second banquet, she had already pleaded for the lives of her people—a request that came after the king had promised three times to do whatever she asked. On the other hand, Esther’s request was nearly impossible to grant. A law of Medes and Persia could not be revoked.

The king managed, however, to find a solution for the problem. Haman’s edict could not be revoked, but Esther and Mordecai could write a new edict by which they could offer protection to the Jews.