A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
est 5:1ESTHER INVITES THE KING AND HAMAN TO A BANQUET. (Est 5:1-14)
Esther put on her royal apparel--It was not only natural, but, on such occasions, highly proper and expedient, that the queen should decorate herself in a style becoming her exalted station. On ordinary occasions she might reasonably set off her charms to as much advantage as possible; but, on the present occasion, as she was desirous to secure the favor of one who sustained the twofold character of her husband and her sovereign, public as well as private considerations--a regard to her personal safety, no less than the preservation of her doomed countrymen--urged upon her the propriety of using every legitimate means of recommending herself to the favorable notice of Ahasuerus.
the king sat upon his royal throne in the royal house, over against the gate of the house--The palace of this Persian king seems to have been built, like many more of the same quality and description, with an advanced cloister, over against the gate, made in the fashion of a large penthouse, supported only by one or two contiguous pillars in the front, or else in the center. In such open structures as these, in the midst of their guards and counsellors, are the bashaws, kadis, and other great officers, accustomed to distribute justice, and transact the public affairs of the provinces [SHAW, Travels]. In such a situation the Persian king was seated. The seat he occupied was not a throne, according to our ideas of one, but simply a chair, and so high that it required a footstool. It was made of gold, or, at least, inlaid with that metal, and covered with splendid tapestry, and no one save the king might sit down on it under pain of death. It is often found pictured on the Persepolitan monuments, and always of the same fashion.
est 5:2the king held out to Esther the golden sceptre that was in his hand--This golden scepter receives an interesting illustration from the sculptured monuments of Persia and Assyria. In the bas-reliefs of Persepolis, copied by Sir Robert Ker Porter, we see King Darius enthroned in the midst of his court, and walking abroad in equal state; in either case he carries in his right hand a slender rod or wand, about equal in length to his own height, ornamented with a small knob at the summit. In the Assyrian alabasters, those found at Nimroud as well as those from Khorsabad, "the great king" is furnished with the same appendage of royalty, a slender rod, but destitute of any knob or ornament. On the Khorsabad reliefs the rod is painted red, doubtless to represent gold; proving that "the golden sceptre" was a simple wand of that precious metal, commonly held in the right hand, with one end resting on the ground, and that whether the king was sitting or walking. "The gold sceptre" has received little alteration or modification since ancient times [GOSS]. It was extended to Esther as a token not only that her intrusion was pardoned, but that her visit was welcome, and a favorable reception given to the suit she had come to prefer.
touched the top of the sceptre--This was the usual way of acknowledging the royal condescension, and at the same time expressing reverence and submission to the august majesty of the king.
est 5:3it shall be even given thee to the half of the kingdom--This mode of speaking originated in the Persian custom of appropriating for the maintenance of great men, or royal favorites, one city for his bread, another for his wine, a third for his clothes, &c., so that the phrase denoted great liberality.
est 5:4let the king and Haman come this day unto the banquet that I have prepared for him--There was great address in this procedure of Esther's; for, by showing such high respect to the king's favorite, she would the better insinuate herself into the royal affections; and gain a more suitable opportunity of making known her request.
est 5:8let the king and Haman come to the banquet that I shall prepare--The king ate alone, and his guests in an adjoining hall; but they were admitted to sit with him at wine. Haman being the only invited guest with the king and queen, it was natural that he should have been elated with the honor.