'Sackcloth' in the Bible

"Woe to you, Chorazin! Woe to you, Bethsaida! If the miracles done in you had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes.

"Woe to you, Chorazin! Woe to you, Bethsaida! For if the miracles done in you had been done in Tyre and Sidon, they would have repented long ago, sitting in sackcloth and ashes.

Then I looked when the Lamb opened the sixth seal, and a huge earthquake took place; the sun became as black as sackcloth made of hair, and the full moon became blood red;

And I will grant my two witnesses authority to prophesy for 1,260 days, dressed in sackcloth.