'Ashes' in the Bible

The nations will be burned to ashes; like thorn bushes that have been cut down, they will be set on fire.

He feeds on ashes; his deceived mind misleads him. He cannot rescue himself, nor does he say, 'Is this not a false god I hold in my right hand?'

Is this really the kind of fasting I want? Do I want a day when people merely humble themselves, bowing their heads like a reed and stretching out on sackcloth and ashes? Is this really what you call a fast, a day that is pleasing to the Lord?

to strengthen those who mourn in Zion, by giving them a turban, instead of ashes, oil symbolizing joy, instead of mourning, a garment symbolizing praise, instead of discouragement. They will be called oaks of righteousness, trees planted by the Lord to reveal his splendor.