See also verses 8 and 12.
1. Lowth (W.) calls attention to an illustration of court etiquette contained in this text as compared with Esther 1:1919If it please the king, let there go a royal commandment from him, and let it be written among the laws of the Persians and the Medes, that it be not altered, That Vashti come no more before king Ahasuerus; and let the king give her royal estate unto another that is better than she. (Esther 1:19). Here the expression “Medes and Persians” is used, the Medes being named first because Darius was a Mede. In the other instance, in the book of Esther, the expression is “Persians and Medes,” Persians being named first out of compliment to Ahasuerus, who was a Persian.
2. The strict etiquette of the Persian court obliged the king never to revoke an order once given, however much he might regret it, because in so doing he would contradict himself, and, according to Persian notions, the law could not contradict itself. A curious instance of the unchangeable character of the Medo-Persian law is here seen in the fact that, after Ahasuerus had issued the order directing the cruel slaughter of the Jews, (Esther 3:1313And the letters were sent by posts into all the king's provinces, to destroy, to kill, and to cause to perish, all Jews, both young and old, little children and women, in one day, even upon the thirteenth day of the twelfth month, which is the month Adar, and to take the spoil of them for a prey. (Esther 3:13)) he would not reverse it, even at the urgent request of his queen (Esther 8:55And said, If it please the king, and if I have found favor in his sight, and the thing seem right before the king, and I be pleasing in his eyes, let it be written to reverse the letters devised by Haman the son of Hammedatha the Agagite, which he wrote to destroy the Jews which are in all the king's provinces: (Esther 8:5)), but he issued another edict in which he granted the Jews permission “to gather themselves together, and to stand for their life” (Esther 8:1111Wherein the king granted the Jews which were in every city to gather themselves together, and to stand for their life, to destroy, to slay, and to cause to perish, all the power of the people and province that would assault them, both little ones and women, and to take the spoil of them for a prey, (Esther 8:11)). Thus the first irreversible edict was ‘completely neutralized by another just as irreversible as itself; and the king continued to act his part as a character but little short of divinely: infallible, immutable, and wholly free from the weakness of repentance!