'Ashes' in the Bible

That kind of man (the idolater) feeds on ashes [and is satisfied with ashes]! A deceived mind has led him astray, so that he cannot save himself, or ask, “Is this thing [that I am holding] in my right hand not a lie?”

“Is a fast such as this what I have chosen, a day for a man to humble himself [with sorrow in his soul]?Is it only to bow down his head like a reedAnd to make sackcloth and ashes as a bed [pretending to have a repentant heart]?Do you call this a fast and a day pleasing to the Lord?

To grant to those who mourn in Zion the following:To give them a turban instead of dust [on their heads, a sign of mourning],The oil of joy instead of mourning,The garment [expressive] of praise instead of a disheartened spirit.So they will be called the trees of righteousness [strong and magnificent, distinguished for integrity, justice, and right standing with God],The planting of the Lord, that He may be glorified.