'Ashes' in the Bible

He feeds on ashes. A deceived heart has turned him aside; and he can't deliver his soul, nor say, "Isn't there a lie in my right hand?"

Is such the fast that I have chosen? the day for a man to afflict his soul? Is it to bow down his head as a rush, and to spread sackcloth and ashes under him? Will you call this a fast, and an acceptable day to Yahweh?

to appoint to those who mourn in Zion, to give to them a garland for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness; that they may be called trees of righteousness, the planting of Yahweh, that he may be glorified.