Esther 5:14

5:14 Haman’s wife Zeresh and all his friends said to him, “Have a gallows seventy-five feet high built, and in the morning tell the king that Mordecai should be hanged on it. Then go with the king to the banquet contented.”

It seemed like a good idea to Haman, so he had the gallows built.

Esther 10:3

10:3 Mordecai the Jew was second only to King Ahasuerus. He was the highest-ranking Jew, and he was admired by his numerous relatives. He worked enthusiastically for the good of his people and was an advocate for the welfare of all his descendants.