'Sackcloth' in the Bible

Now when Mordecai found out all that was done, Mordecai tore his clothes, and put on sackcloth with ashes, and went out into the midst of the city, and wailed loudly and a bitterly.

He came even before the king's gate, for no one is allowed inside the king's gate clothed with sackcloth.

In every province, wherever the king's commandment and his decree came, there was great mourning among the Jews, and fasting, and weeping, and wailing; and many lay in sackcloth and ashes.

Esther's maidens and her eunuchs came and told her this, and the queen was exceedingly grieved. She sent clothing to Mordecai, to replace his sackcloth; but he didn't receive it.