וַיִּכְתֹּ֣ב מָרְדֳּכַ֔י אֶת־הַדְּבָרִ֖ים הָאֵ֑לֶּה וַיִּשְׁלַ֨ח סְפָרִ֜ים אֶל־כָּל־הַיְּהוּדִ֗ים אֲשֶׁר֙ בְּכָל־מְדִינוֹת֙ הַמֶּ֣לֶךְ אֲחַשְׁוֵר֔וֹשׁ הַקְּרוֹבִ֖ים וְהָרְחוֹקִֽים׃
And Mordecai wrote these things, and sent letters unto all the Jews that were in all the provinces of the king Ahasuerus, both nigh and far,
Read halakhic rulings (Jewish law) on Esther 9:20: and classical halakhic sources.