John Gill, on Esth 3:13

And the letters were sent by post into all the king's provinces,.... Or by the runners (x); by which it seems as if these letters were carried by running footmen, men swift of foot; or rather they were running horses, on which men rode post with letters, and which the Persians called Angari; a scheme invented by Cyrus, for the quick dispatch of letters from place to place, by fixing horses and men to ride them at a proper distance, to receive letters one from another, and who rode night and day (y), as our mail men do now; and nothing could be swifter, or done with greater speed; neither snow, nor rain, nor heat, nor night, could stop their course, we are told (z): the purport of these letters was: to destroy, to kill, and to cause to perish, all Jews, both young and old, little children and women, in one day, even upon the thirteenth day of the twelfth month, which is the month Adar; see Est 3:7. The orders were to destroy, by any means whatsoever, all the Jews, of every age and sex, all in one day, in all the provinces which are here named, that they might be cut off with one blow: and to take the spoil of them for a prey; to be their own booty; which was proposed to engage them in this barbarous work, to encourage them in it to use the greater severity and dispatch. (x) "in manu cursorum", Montanus; so the Tigurine version, Drusius, V. L. Junius & Tremellius, Piscator. (y) Xenophon. Cyropaedia, l. 8. c. 43. (z) Herodot. Urania, sive, l. 8. c. 98.