C. F. Keil and Franz Delitzsch on Esther 9:23

Est 9:23

And the Jews undertook to do as they had begun, and as Mordochai had written to them. They had begun, as Est 9:22 tells us, by keeping both days, and Mordochai wrote to them that they should make this an annual custom. This they agreed to do in consequence of Mordochai’s letters. The reason of their so doing is given in Est 9:24 and Est 9:25, and the name of this festival is explained, Est 9:26, by a brief recapitulation of the events which gave rise to it. Then follows, Est 9:26 and Est 9:27, another wordy statement of the fact, that it was by reason of this letter, and on account of what they had seen, i.e., experienced, that the annual celebration of this feast was instituted for a perpetual memorial to all Jews at all times (Est 9:28 and Est 9:29).