'Ashes' in the Bible

He feedeth on ashes; a deceived heart hath turned him aside; and he cannot deliver his soul, nor say, Is there not 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? wilt thou call this a fast, and an acceptable day to Jehovah?

to appoint unto them that mourn in Zion, to give unto 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 Jehovah, that he may be glorified.