What Is Sackcloth in the Bible?
Object
A rough cloth made of goat’s hair, worn as a garment of penance or mourning.
Where it appears in the Bible
Genesis 37:34; Jonah 3:5
What the Bible says
Genesis 37:34
And tearing his garments, he put on sackcloth, mourning for his son a long time.
Jonah 3:5
And the men of Ninive believed in God: and they proclaimed a fast, and put on sackcloth from the greatest to the least.
Douay-Rheims Bible (Challoner revision), public domain.
Source: RAE, “cilicio”