Esther 9:20-23

And Mordecai wrote these things and sent letters to all the Jews, near and far, who were in all the provinces of King Ahasuerus, to establish among them that they should celebrate yearly the fourteenth and fifteenth days of the month of Adar, as the days on which the Jews had rest from their enemies, as the month which was turned from sorrow to joy for them, and from mourning to a holiday; that they should make them days of feasting and joy, of sending presents to one another and gifts to the poor. So the Jews accepted the custom which they had begun, as Mordecai had written to them