C. F. Keil and Franz Delitzsch on Esther 9:5

Est 9:5

Thus supported, the Jews inflicted defeat upon their enemies with the sword, and with slaughter and destruction. הכּה with בּ, to deal a blow upon or against some one, to cause or bring about upon enemies a defeat; comp. e.g., 2Sa 23:10; 2Sa 24:17; Num 22:6. The notion is strengthened by וגו מכּת־חרב, literally, to strike a stroke of the sword, and of slaughter, and of destruction, in accordance with the decree, Est 8:11. “And did according to their will to those that hated them,” i.e., retaliated upon their enemies at their discretion.