'Sackcloth' in the Bible

When the king heard what the woman said, he ripped his garments as he continued walking along the city wall. As the people watched, all of a sudden they noticed he was wearing sackcloth underneath his clothes, inside next to his flesh!

When King Hezekiah heard Eliakim's report, he tore his clothes, put on a sackcloth covering, entered the LORD's Temple,

and sent Eliakim the household supervisor, Shebna the scribe, and the elders of the priests all of them covered in sackcloth to Amoz's son, the prophet Isaiah.