For the moment, Esther refrained from uttering her petition. All she asked was, that the king and Haman would come to a banquet she proposed to give. She had good reasons for this peculiar course of conduct. She desired to disarm Haman's suspicions regarding her Jewish descent, and to lead her fellow-Jews to fix their hope upon God and not upon her. At the same time, it was her plan to arouse jealousy of Haman in both the king and the princes. She was quite ready to sacrifice her own life, if her stratagems would but involve the life of Haman, too. At the banquet she therefore favored Haman in such manner that Ahasuerus could not but be jealous. She moved her chair close to Haman's, and when Ahasuerus handed her his wine-cup, to let her drink of it first, she passed it on to his minister.
Esther at the Temple
Legends of the Jews 12:185