Wherefore they called these days Purim after the name of Pur. Therefore for all the words of this letter, and of that which they had seen concerning this matter, and which had come unto them,

Wesley's Notes

9:26 Pur - This Persian word signifies a lot, because Haman had by lot determined this time to be the time of the Jews destruction.

King James Translators' Notes

Pur: that is, Lot

Jamieson-Fausset-Brown Bible Commentary

26. they called these days Purim after the name of Pur-"Pur," in the Persian language, signifies "lot"; and the feast of Purim, or lots, has a reference to the time having been pitched upon by Haman through the decision of the lot. In consequence of the signal national deliverance which divine providence gave them from the infamous machinations of Haman, Mordecai ordered the Jews to commemorate that event by an anniversary festival, which was to last for two days, in accordance with the two days' war of defense they had to maintain. There was a slight difference in the time of this festival; for the Jews in the provinces, having defended themselves against their enemies on the thirteenth, devoted the fourteenth to festivity; whereas their brethren in Shushan, having extended that work over two days, did not observe their thanksgiving feast till the fifteenth. But this was remedied by authority, which fixed the fourteenth and fifteenth of Adar. It became a season of sunny memories to the universal body of the Jews; and, by the letters of Mordecai, dispersed through all parts of the Persian empire, it was established as an annual feast, the celebration of which is kept up still. On both days of the feast, the modern Jews read over the Megillah or Book of Esther in their synagogues. The copy read must not be printed, but written on vellum in the form of a roll; and the names of the ten sons of Haman are written on it a peculiar manner, being ranged, they say, like so many bodies on a gibbet. The reader must pronounce all these names in one breath. Whenever Haman's name is pronounced, they make a terrible noise in the synagogue. Some drum with their feet on the floor, and the boys have mallets with which they knock and make a noise. They prepare themselves for their carnival by a previous fast, which should continue three days, in imitation of Esther's; but they have mostly reduced it to one day [Jennings, Jewish Antiquities].

Matthew Henry's Concise Commentary

9:20-32 The observance of the Jewish feasts, is a public declaration of the truth of the Old Testament Scriptures. And as the Old Testament Scriptures are true, the Messiah expected by the Jews is come long ago; and none but Jesus of Nazareth can be that Messiah. The festival was appointed by authority, yet under the direction of the Spirit of God. It was called the feast of Purim, from a Persian word, which signifies a lot. The name of this festival would remind them of the almighty power of the God of Israel, who served his own purposes by the superstitions of the heathen. In reviewing our mercies, we should advert to former fears and distresses. When our mercies are personal, we should not by forgetfulness lose the comfort of them, or withhold from the Lord the glory due to his name. May the Lord teach us to rejoice, with that holy joy which anticipates and prepares for the blessedness of heaven. Every instance of Divine goodness to ourselves, is a new obligation laid on us to do good, to those especially who most need our bounty. Above all, redemption by Christ binds us to be merciful, 2Co 8:9.