What did they tell Haman?
Vilna Gaon: He should supervise and see that he does not bow. Haman did not see this due to his great pride.
Malbim: It was not amidst hatred. Rather, he imposed on them to guard the king's command and protect against those who transgress his will. Therefore, they warned Mordechai first. to
What is the meaning of "ha'Ya'amdu Divrei Mordechai"?
Rashi: He says that he will never bow, for he is a Yehudi, and he is commanded about idolatry 1 !
Malbim: They said that this is fine when Haman is afar and cannot see. Then bowing would be l'Shem idolatry. However, when he is close, one bows due to his authority! It is normal to bow in front of every officer. Refusing to bow when he is near is Mored b'Malchus! They told Haman to come close to Mordechai. If he will bow, this will affirm his words and excuse, that he refuses only due to idolatry, because he is a Yehudi.
Also Bnei Noach are commanded! Perhaps Rashi means that he is commanded even about offshoots of idolatry. (PF)
Why does it say "Ki Higid Lahem"?
Vilna Gaon: The reason they told Haman is because [Mordechai] told them that he is a Yehudi. Anyone who denies idolatry is called Yehudi (Megilah 13a).
