"King Xerxes replied to Queen Esther and to Mordecai the Jew, 'Because Haman attacked the Jews, I have given his estate to Esther, and they have hanged him on the gallows. Now write another decree in the king's name in behalf of the Jews as seems best to you, and seal it with the king's signet ring - for no document written in the king's name and sealed with his ring can be revoked.'" NIV translation
The king could not cancel the law that had been issued but he authorized a new law on behalf of the Jews. This is a picture of the coming grace of God through Jesus Christ. The Law was given to make us aware of sin and the fact that we were destined for death. That Law was not cancelled but God issued a new law which said that those who believe in Jesus Christ would be saved from death.
"At once the royal secretaries were summoned - on the twenty-third day of the third month, the month of Sivan. They wrote out all Mordecai's orders to the Jews, and to the satraps, governors and nobles of the 127 provinces stretching from India to Cush. These orders were written in the script of each province and the language of each people and also to the Jews in their own script and language." NIV translation
Mordecai wasted no time in writing the order that would save the Jews from death and destruction. This happened in the same month that God had given the Jews the Law at Mt. Sinai. Once again, it was written in all the different languages so that everyone would understand it.
"Mordecai wrote in the name of King Xerxes, sealed the dispatches with the king's signet ring, and sent them by mounted couriers, who rode fast horses especially bred for the king." NIV translation
The message was carried to the ends of the kingdom as fast as possible. There was not much time and so it was all done with that in mind. It reminds me of the job that we have been given to tell the world about Jesus and how they can be saved from the coming destruction. We need to carry the message with haste just as the riders on these horses did because we do not know when it will be too late. It could be today that Jesus comes back!