Bible Verses About Sackcloth: By God's prophets

"He was a hairy man," they answered him, "with a leather belt around his waist." He said, "It was Eliyahu from Tishbe."

It was at that time that ADONAI, speaking through Yesha'yahu the son of Amotz, said, "Go and unwind the sackcloth from around your waist, and take your sandals off your feet." So he did it, going about unclothed and barefoot.

Yochanan wore clothes of camel's hair with a leather belt around his waist, and his food was locusts and wild honey.

“Also I will give power to my two witnesses; and they will prophesy for 1,260 days, dressed in sackcloth.”