Sackcloth

SACK'CLOTH, noun [sack and cloth.] Cloth of which sacks are made; coarse cloth. This word is chiefly used in Scripture to denote a cloth or garment worn in mourning, distress or mortification.

Gird you with sackcloth and mourn before Abner. [[2 Samuel 3#31|2 Samuel 3:31]].

[[Esther 4#1|Esther 4:1]]. [[Job 16#15|Job 16:15]].