'Fasting' in the Bible

In every province where the order of the king and his edict reached, among the Jewish people there was great mourning, fasting, weeping, and lamenting, and many lay down on sackcloth and ashes.

establishing these days of Purim at the prescribed time, just as Mordecai the Jew and Queen Esther had established, and just as the Jewish people had established for themselves and for their descendants. The letter included instructions for their fasting and lamentations.