Commentators (such as this one) frequently imply that the ten sons of Haman were executed as an act of revenge. Indeed, the Book of Esther does say:
Then Esther said: “If it pleases the king… let Haman's ten sons be hanged upon the gallows.” And the king commanded it so to be done… and they hanged Haman's ten sons. [Esther 9:13-14]
But this quote may lead to the (false) conclusion that Haman’s ten sons (babes in arms for all we know) were killed on account of their father’s actions. In reality, Haman’s ten sons had already died in battle fighting the Jews. Esther just wanted to have their bodies hung. This is made clear in an earlier quote:
The Jews struck all their enemies with the stroke of the sword… and did what they would to those who hated them… [Esther 9:5]
The ten sons of Haman…, the enemy of the Jews, they slew [in battle], but on the plunder they did not lay their hand. [Esther 9:10]
Is this point highlighted anywhere?