'Sackcloth and Ashes' in the Bible

When Mordecai learned all that had been done, he tore his garments and clothed himself in sackcloth and ashes. He went into the middle of the city and cried out with a loud and bitter cry.

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.