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 6:1AHASUERUS REWARDS MORDECAI FOR FORMER SERVICE. (Est 6:1-14)
the king . . . commanded to bring the book of records of the chronicles--In Eastern courts, there are scribes or officers whose duty it is to keep a journal of every occurrence worthy of notice. A book of this kind, abounding with anecdotes, is full of interest. It has been a custom with Eastern kings, in all ages, frequently to cause the annals of the kingdom to be read to them. It is resorted to, not merely as a pastime to while away the tedium of an hour, but as a source of instruction to the monarch, by reviewing the important incidents of his own life, as well as those of his ancestors. There was, therefore, nothing uncommon in this Persian monarch calling for the court journal. But, in his being unable to sleep at that particular juncture, in his ordering the book then to be read to him, and in his attention having been specially directed to the important and as yet unrewarded services of Mordecai, the immediate interposition of Providence is distinctly visible.
est 6:4Now Haman was come into the outward court--This was early in the morning. It is the invariable custom for kings in Eastern countries to transact business before the sun is hot, often in the open air, and so Haman was in all probability come officially to attend on his master.
est 6:6What shall be done unto the man whom the king delighteth to honour?--In bestowing tokens of their favor, the kings of Persia do not at once, and as it were by their own will, determine the kind of honor that shall be awarded; but they turn to the courtier standing next in rank to themselves, and ask him what shall be done to the individual who has rendered the service specified; and according to the answer received, the royal mandate is issued.
est 6:8the royal apparel . . . which the king useth to wear--A coat which has been on the back of a king or prince is reckoned a most honorable gift, and is given with great ceremony.
the horse that the king rideth upon--Persia was a country of horses, and the highbred charger that the king rode upon acquired, in the eyes of his venal subjects, a sort of sacredness from that circumstance.
and the crown royal which is set upon his head--either the royal turban, or it may be a tiara, with which, on state processions, the horse's head was adorned.
est 6:9delivered to the hand of one of the king's most noble princes . . . array the man--On grand and public occasions, the royal steed is led by the highest subject through the principal streets of the city, a ceremony which may occupy several hours.
est 6:11Then Haman took, &c.--This sudden reverse, however painful to Haman as an individual, is particularly characteristic of the Persian manners.
est 6:14came the king's chamberlains, and hasted to bring Haman unto the banquet that Esther had prepared--Besides the invitation given to an entertainment, a message is always sent to the guests, immediately at the day and hour appointed, to announce that all things are ready.