sackcloth and ashes, to be in

sackcloth and ashes, to be in

To be penitent or contrite; in a state of repentance. This term alludes to the ancient Hebrew custom of donning a coarse, dark cloth from which sacks were made and dusting oneself with ashes to signify one’s humility before God. It is mentioned in the Bible: “And I set my face unto the Lord God, to seek by prayer and supplications, with fasting, and sackcloth, and ashes” (Daniel 9:3). The term may be obsolescent.
See also: and, sackcloth