'Sackcloth' in the Bible

When the king heard what the woman said, he tore his clothes. As he was passing by on the wall, the people could see he was wearing sackcloth under his clothes.

When King Hezekiah heard this, he tore his clothes, put on sackcloth, and went to the Lord's temple.

He sent Eliakim the palace supervisor, Shebna the scribe, and the leading priests, clothed in sackcloth, with this message to the prophet Isaiah son of Amoz: