'Clothed with Sackcloth' in the Bible

He went [only] as far as the king’s gate, because no one was to enter the king’s gate dressed in sackcloth.

Then he sent Eliakim, who was in charge of the [royal] household, and Shebna the scribe, and the elders of the priests, covered with sackcloth, to Isaiah the prophet, the son of Amoz.