The entire book of Esther is about God’s providential care of His people.
These chapters look prophetically to the day of the Lord. This will be a day when God will come in wrath and will judge the wicked. However, all is not lost. Those who fear the Lord will be remembered and will be spared. To them, the Sun of righteousness will rise will healing and will care for them as calves that are brought up in the stall. In closing, they are told to look backward to the law of Moses and forward to the coming of Elijah as the herald of the day of the Lord and the Messianic Kingdom to follow.
Haman has been destroyed and the Jews have been delivered. That which was the cause for great sorrow has become an occasion of great gladness. This working of God in things that are thought of as chance must be celebrated. We must remember what kind of a God we have.
This chapter deals with the dangerous consequences of pride and the need for humility concerning self and praise and admiration toward the greatness of God. Nebuchadnezzar tells the story as a personal testimony. He tells how the most powerful man in the world (himself) was brought low in a moment by God, and how he was restored to his former position—though as a wiser man than before.
What a difference we see between Saul and David. One impressed men by his exterior appearance; the other impressed God by the condition of his heart.