The prophet Isaiah, on the other hand, critiques the use of sackcloth and ashes as inadequate to please God, but in the process he indicates that this practice was well-known in Israel: "Is this the manner of fasting I wish, of keeping a day of penance: that a man bow his head like a reed, and lie in sackcloth and ashes? Do you call this a fast, a day acceptable to the Lord?" (Is 58:5).
The prophet Daniel pleaded for God to rescue Israel with sackcloth and ashes as a sign of Israel's repentance: "I turned to the Lord God, pleading in earnest prayer, with fasting, sackcloth and ashes" (Dn 9:3).
Perhaps the best known example of repentance in the Old Testament also involves sackcloth and ashes. When the prophet Jonah finally obeyed God's command and preached in the great city of Nineveh, his preaching was amazingly effective. Word of his message was carried to the king of Nineveh. "When the news reached the king of Nineveh, he rose from his throne, laid aside his robe, covered himself with sackcloth, and sat in the ashes" (Jon 3:6).
In the book of Judith, we find acts of repentance that specify that the ashes were put on people's heads: "And all the Israelite men, women and children who lived in Jerusalem prostrated themselves in front of the temple building, with ashes strewn on their heads, displaying their sackcloth covering before the Lord" (Jdt 4:11; see also 4:15 and 9:1).
Just prior to the New Testament period, the rebels fighting for Jewish independence, the Maccabees, prepared for battle using ashes: "That day they fasted and wore sackcloth; they sprinkled ashes on their heads and tore their clothes" (1 Mc 3:47; see also 4:39).
In the New Testament, Jesus refers to the use of sackcloth and ashes as signs of repentance: "Woe to you, Chorazin! Woe to you, Bethsaida! For if the mighty deeds done in your midst had been done in Tyre and Sidon, they would long ago have repented in sackcloth and ashes" (Mt 11:21, Lk 10:13).