'Ashes' in the Bible

And he gave a sign the same day, saying, This is the sign which the LORD hath spoken; Behold, the altar shall be rent, and the ashes that are upon it shall be poured out.

The altar also was rent, and the ashes poured out from the altar, according to the sign which the man of God had given by the word of the LORD.

So the prophet departed, and waited for the king by the way, and disguised himself with ashes upon his face.

And he hasted, and took the ashes away from his face; and the king of Israel discerned him that he was of the prophets.