Ash Wednesday is a sign of repentance and biblical. “Ash Wednesday derives its name from the practice of blessing ashes made from palm branches blessed on the previous year’s Palm Sunday, and placing them on the heads of participants to the accompaniment of the words “Repent, and believe in the Gospel” or “Remember that you are dust, and to dust you shall return,” Genesis 3:19.
Ash Wednesday is observed by fasting, abstinence from something, and repentance.
Biblical significance of ashes: Ashes were used in ancient times to express grief. When Tamar was raped by her half-brother she sprinkled ashes on her head, tore her robe, and with her face buried in her hands went away crying” 2 Samuel 13:19. The gesture was also used to express sorrow for sins and faults. In Job 42:3–6 Job says to God, “I have heard of thee by the hearing of the ear: but now mine eye seeth thee. Wherefore I abhor myself, and repent in dust and ashes.” The prophet Jeremiah 6:26 calls for repentance by saying, “O daughter of my people, gird on sackcloth, roll in the ashes.” The prophet Daniel 9:3 recounted pleading to God, “I turned to the Lord God, pleading in earnest prayer, with fasting, sackcloth and ashes.” Just prior to the New Testament period, the rebels fighting for Jewish independence prepared for battle using ashes. Examples of the practice among Jews are found in several other books of the Bible, including Numbers 19:9, 19:17, Jonah 3:6, Esther 4:1, and Hebrews 9:13. Jesus is quoted as speaking of the practice in Matthew 11:21 and Luke 10:13: “If the mighty works done in you had been done in Tyre and Sidon, they would have repented long ago (sitting) in sackcloth and ashes.
Christians continued the practice of using ashes as an external sign of repentance.”