What Do We Learn from Haman's Downfall?

Whatever is done in this world is for the benefit of the tzadikim. Tzadikim mean the Jewish people. That is lesson number one. The lesson of Haman’s wealth was NOT lost from Mordechai and his people. When Mordechai finally inherited all the estate of Haman, it was to impress on us the teaching that EVERYTHING in the world was created for us. — Preface to Purim 2 (#112)