A sort of coarse stuff made of goats hair, of a black or dark colour, worn by soldiers and mariners; and used as a habit among the Hebrews in times of mourning and distress. It was called sackcloth, either because sacks were made of this sort of stuff, or because haircloaths were straight and close like a sack. Calmet.
To augment her painful penance more,
Thrice every week in ashes she did sit,
And next her wrinkled skin rough sackcloth wore. F. Queen.
Thus with sackcloath I invest my woe,
And dust upon my clouded forehead throw. Sandys.
Being clad in sackcloath, he was to lie on the ground, and constantly day and night to implore God's mercy for the sin he had committed. Ayliffe's Parergon.