What is the significance of sackcloth and ashes in the Bible?

from the old testament

• Sackcloth and ashes were a culturally established practice in the ancient Near East for expressing one’s sorrow. For example, when Job was afflicted with trials and the death of his children, his response was to tear his clothes and sit in ashes (Job 1:20; 2:8).
• The practice also displayed repentance. An example of that is found when Nineveh’s king removed his royal clothes to humble himself like the poorest man, donning sackcloth and sitting in ashes (Jonah 3:6). He also commanded others to do the same in the hope that God would see their repentance and relent in His judgment (Jonah 3:7–9).
• Such external signs were also used symbolically of God’s coming judgment. For example, Isaiah was commanded to wear sackcloth as a sign of the doom that would befall Egypt and Cush (Isaiah 20:1–4).
• However, because they were external signs, one could “fake” repentance or sorrow. Through Joel, God commanded Israel: “return to me with all your heart, with fasting, with weeping, and with mourning; and rend your hearts and not your garments” (Joel 2:12–13a).
• Other examples of sackcloth and ashes are given by Daniel (Daniel 9:3), Esther (Esther 4:1–3), and Nehemiah (Nehemiah 9:1). They each humbled themselves in the context of intercession and crisis.

from the new testament

• While sackcloth and ashes were an Old Testament custom, Jesus drew from it to condemn Chorazin and Bethsaida. He said, “Woe to you, Chorazin! Woe to you, Bethsaida! For if the mighty works done in you had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes” (Matthew 11:20–21).
• Believers are called to have a heart much like the type of heart that sackcloth and ashes were intended to display. Though not using the exact imagery, James said, “Be wretched and mourn and weep. Let your laughter be turned to mourning and your joy to gloom. Humble yourselves before the Lord, and he will exalt you” (James 4:9–10).

implications for today

Sackcloth and ashes provide a vivid image of sorrow. It’s the picture of one so distraught that one wallows in rags and filth. The sorrow is so deep that he or she doesn’t care about outward appearances. It’s also a picture of humility—it’s the poor who are generally found in rags, not the rich. God calls us to have that humility and heart posture of being “poor in spirit” (Matthew 5:3).

Jesus once told a parable in which a Pharisee thanked God that he was not like the sinners (Luke 18:9–12). In his arrogance and lack of self-awareness, that man’s pride displeased God. But there was a hated tax collector nearby beating his chest in sorrow because he knew he was a sinner (Luke 18:13–14). That man was being poor in spirit, and God looked favorably upon him.

What about you? Are you like the Pharisee who sees yourself as better than those sinners over there? Are you assuming that you have somehow earned God’s favor because you are righteous? God says we’re all sinners (Psalm 14:2–3) and the one who is haughty and thinks he is better than others must take heed: destruction is around the corner (Proverbs 16:18).

But are you, instead, like the tax collector, beating your chest? Do you know you are a sinner but don’t know how to escape God’s wrath? Know this: God forgives sinners. When we humble ourselves and admit we are not righteous, and when we, in faith, acknowledge that only Jesus is righteous and that He died in our place so we can be saved from God’s wrath (Romans 5:9), God is pleased (Hebrews 11:6). Therefore, be humble in spirit, figuratively covering yourself in ashes, and seek God!