'Sackcloth' in the Bible

Wail like a virgin [bride] clothed with sackclothFor the bridegroom of her youth [who has died].

Clothe yourselves with sackclothAnd lament (cry out in grief), O priests;Wail, O ministers of the altar!Come, spend the night in sackcloth [and pray without ceasing],O ministers of my God,For the grain offering and the drink offeringAre withheld from the house of your God.