בַּחֹ֤דֶשׁ הָרִאשׁוֹן֙ הוּא־חֹ֣דֶשׁ נִיסָ֔ן בִּשְׁנַת֙ שְׁתֵּ֣ים עֶשְׂרֵ֔ה לַמֶּ֖לֶךְ אֲחַשְׁוֵר֑וֹשׁ הִפִּ֣יל פּוּר֩ ה֨וּא הַגּוֹרָ֜ל לִפְנֵ֣י הָמָ֗ן מִיּ֧וֹם ׀ לְי֛וֹם וּמֵחֹ֛דֶשׁ לְחֹ֥דֶשׁ שְׁנֵים־עָשָׂ֖ר הוּא־חֹ֥דֶשׁ אֲדָֽר׃ (ס)
Rashi on Esther
A pur was cast. Whoever cast, cast, and the verse does not specify who [cast the pur]. This is an abbreviated verse.
Rashi on Esther
Meaning “lot.” Scripture explains; and what is the pur? “That is the lot.” He cast lots [to determine] in which month he would succeed.
Rashi on Esther
For a specific day. On which day of the month he would succeed.4Haman felt gratified when the lot he cast resulted in the month of Adar, because Moshe died in that month so it was obviously an inopportune time for the Jews. (Maseches Megillah 13b)