“Sackcloth and ashes were used in Old Testament times as a symbol of debasement, mourning, and/or repentance. Someone wanting to show his repentant heart would often wear sackcloth, sit in ashes, and put ashes on top of his head. Sackcloth was a coarse material usually made of black goat’s hair, making it quite uncomfortable to wear. The ashes signified desolation and ruin.
When someone died, the act of putting on sackcloth showed heartfelt sorrow for the loss of that person. We see an example of this when David mourned the death of Abner, the commander of Saul’s army (2 Samuel 3:31). Jacob also demonstrated his grief by wearing sackcloth when he thought his son Joseph had been killed (Genesis 37:34). These instances of mourning for the dead mention sackcloth but not ashes.
Ashes accompanied sackcloth in times of national disaster or repenting from sin. Esther 4:1, for instance, describes Mordecai tearing his clothes, putting on sackcloth and ashes, and walking out into the city “wailing loudly and bitterly.” This was Mordecai’s reaction to King Xerxes’ declaration giving the wicked Haman authority to destroy the Jews (see Esther 3:8–15). Mordecai was not the only one who grieved. “In every province to which the edict and order of the king came, there was great mourning among the Jews, with fasting, weeping, and wailing. Many lay in sackcloth and ashes” (Esther 4:3). The Jews responded to the devastating news concerning their race with sackcloth and ashes, showing their intense grief and distress.
Sackcloth and ashes were also used as a public sign of repentance and humility before God. When Jonah declared to the people of Nineveh that God was going to destroy them for their wickedness, everyone from the king on down responded with repentance, fasting, and sackcloth and ashes (Jonah 3:5–7). They even put sackcloth on their animals (verse 8). Their reasoning was, “Who knows? God may yet relent and with compassion turn from his fierce anger so that we will not perish” (verse 9). This is interesting because the Bible never says that Jonah’s message included any mention of God’s mercy; but mercy is what they received. It’s clear that the Ninevites’ donning of sackcloth and ashes was not a meaningless show. God saw genuine change—a humble change of heart represented by the sackcloth and ashes—and it caused Him to “relent” and not bring about His plan to destroy them (Jonah 3:10).
Other people the Bible mentions wearing sackcloth include King Hezekiah (Isaiah 37:1), Eliakim (2 Kings 19:2), King Ahab (1 Kings 21:27), the elders of Jerusalem (Lamentations 2:10), Daniel (Daniel 9:3), and the two witness in Revelation 11:3.
Very simply, sackcloth and ashes were used as an outward sign of one’s inward condition. Such a symbol made one’s change of heart visible and demonstrated the sincerity of one’s grief and/or repentance. It was not the act of putting on sackcloth and ashes itself that moved God to intervene, but the humility that such an action demonstrated (see 1 Samuel 16:7). God’s forgiveness in response to genuine repentance is celebrated by David’s words: “You removed my sackcloth and clothed me with joy” (Psalm 30:11).”
Love & His mercy,
Matthew
Summa Catechetica, "Neque enim quaero intelligere ut credam, sed credo ut intelligam." – St Anselm, "Let your religion be less of a theory, and more of a love affair." -G.K. Chesterton, "I want a laity, not arrogant, not rash in speech, not disputatious, but men and women who know their religion, who enter into it, who know just where they stand, who know what they hold and what they do not, and who know their creed so well that they can give an account of it."- Bl John Henry Newman, Cong. Orat., "Encounter, not confrontation; attraction, not promotion; dialogue, not debate." -cf Pope Francis, "Without good books and spiritual reading, it will be morally impossible to save our souls." —St. Alphonsus Liguori, "God here speaks to souls through…good books“ – St Teresa of Avila, Interior Castle, "You will not see anyone who is really striving after his advancement who is not given to spiritual reading. And as to him who neglects it, the fact will soon be observed by his progress.” -St Athanasius, "To convert someone, go and take them by the hand and guide them." -St Thomas Aquinas, OP. 1 saint ruins ALL the cynicism in Hell & on Earth. “When we pray we talk to God; when we read God talks to us…All spiritual growth comes from reading and reflection.” -St Isidore of Seville, “Also in some meditations today I earnestly asked our Lord to watch over my compositions that they might do me no harm through the enmity or imprudence of any man or my own; that He would have them as His own and employ or not employ them as He should see fit. And this I believe is heard.” -GM Hopkins, SJ, "Only God knows the good that can come about by reading one good Catholic book." — St. John Bosco, "Why don't you try explaining it to them?" – cf St Peter Canisius, SJ, Doctor of the Church, Doctor of the Catechism, "Already I was coming to appreciate that often apologetics consists of offering theological eye glasses of varying prescriptions to an inquirer. Only one prescription will give him clear sight; all the others will give him at best indistinct sight. What you want him to see—some particular truth of the Faith—will remain fuzzy to him until you come across theological eye glasses that precisely compensate for his particular defect of vision." -Karl Keating, "The more perfectly we know God, the more perfectly we love Him." -St Thomas Aquinas, OP, ST, I-II,67,6 ad 3, “But always when I was without a book, my soul would at once become disturbed, and my thoughts wandered." —St. Teresa of Avila, "Let those who think I have said too little and those who think I have said too much, forgive me; and let those who think I have said just enough thank God with me." –St. Augustine, "Without good books and spiritual reading, it will be morally impossible to save our souls." —St. Alphonsus Liguori "Never read books you aren't sure about. . . even supposing that these bad books are very well written from a literary point of view. Let me ask you this: Would you drink something you knew was poisoned just because it was offered to you in a golden cup?" -St. John Bosco " To teach in order to lead others to faith is the task of every preacher and of each believer." —St. Thomas Aquinas, OP. "Prayer purifies us, reading instructs us. Both are good when both are possible. Otherwise, prayer is better than reading." –St. Isidore of Seville “The aid of spiritual books is for you a necessity.… You, who are in the midst of battle, must protect yourself with the buckler of holy thoughts drawn from good books.” -St. John Chrysostom