There seem to be at least two purposes for the book. First, it demonstrates God's providential care of His people even when they were outside the Promised Land because of disobedience. Second, it explains the origin of the feast of Purim with a view to commending its observance to the Jews (9:24-28).9Ancient histories, the Greek history of Herodotus being one, were often written "for public recitation at private gatherings or public festivals."10Esther was evidently written for the same purpose. The Jews retold the story of Esther at Purim each year.
"The importance of the book for modern historians can be gauged by the fact that, whereas Josephus included the Esther story in his Antiquities of the Jews, Martin Noth in his History of Israelmakes no mention of it, and Geo Widengren dismisses it in thirteen lines. It is without much historical value.'11John Bright mentions the book by name but that is all.12Whatever others say, in practice historians ignore the book of Esther. Whatever the reason for this neglect of the book may be, we are justified in assuming that present-day historians do not take seriously the threat it records to the very existence of the Jewish race."13
A third purpose may be to warn readers against anti-Semitism (cf. Gen. 12:1-3).
"Esther says to the Christian that anti-Jewish hostility is intolerable to God."14
"It is easy to see why the book is valued by Jews, who have suffered so much through the ages and have clung to the assurance implied by Purim that, however severe the threat upon their race, they have a future."15
