Charles Ellicott Commentary Esther 9:26

"Wherefore they called these days Purim, after the name of Pur. Therefore because of all the words of this letter, and of that which they had seen concerning this matter, and that which had come unto them," — Esther 9:26 (ASV)

Purim. —As we have already stated, the festival of Purim is still observed by the Jews, on the 14th and 15th of Adar, the preceding day being kept as a fast. At Purim, the whole Book of Esther is read through in the service in the synagogues, a custom that can be traced back at any rate to the Christian era (Josephus, Ant. xi. 6. 13; Mishna, Bosh ha-Shanah, iii. 7).