A fine powder that is left after something has been completely burned. The burning of sacrificial offerings on the tabernacle or temple altar produced ashes that had to be thrown out in a ceremony (Leviticus 1:16; 4:12; 6:10–11; compare Hebrews 9:13). The ashes on pagan altars are mentioned in several Old Testament stories (1 Kings 13:1–5; 2 Kings 23:4). When Moses threw ashes into the air during the contest with the Egyptian pharaoh, the ashes spread like fine dust across all of Egypt. This caused a plague of boils to appear on both people and animals. (Exodus 9:8–10).
In the Bible, ashes are often mentioned as a sign of deep grief, repentance, humiliation, or feeling worthless. People would put ashes on themselves to show these intense emotions. The Bible sometimes uses ashes and dust in similar ways. For example:
Tamar put ashes on herself to show how upset she was after being sexually assaulted by her half-brother (2 Samuel 13:19).
Mordecai covered himself with ashes because he was very worried after the king had ordered all the Jewish people in his kingdom to be killed (Esther 4:1–3)
Daniel put ashes on himself when he prayed to God for his people who were forced to live in a foreign country (Daniel 9:3)
The king of Nineveh put ashes on himself to show he was sorry for his wrong actions after he heard Jonah's message from God (Jonah 3:6; compare Luke 10:13)
People in the Bible also used ashes as a symbol to represent different ideas:
Feeling humble or small (Genesis 18:27)
Feeling worthless or like something has no use (Job 13:12; 30:19; Isaiah 44:20)
Destruction (Ezra 28:18; 2 Peter 2:6)