XXash-iz: Among the ancient Hebrews #and other Orientals, to sprinkle with or sit in ashes was a mark or token of grief, humiliation, or penitence. Ashes on the head was one of the ordinary signs of mourning for the dead, as when "Tamar put ashes on her head .... and went on crying" (2 Sam 13:19 the King James Version), and of national humiliation, as when the children of Israel were assembled under Nehemiah "with fasting, and with sackcloth, and earth (ashes) upon them" (Neh 9:1), and when the people of Nineveh repented in sackcloth and ashes at the preaching of Jonah (Jon 3:5,6; compare 1 Macc 3:47). The afflicted or penitent often sat in ashes (compare Job 2:8; 42:6: "I abhor myself, and repent in dust and ashes"), or even wallowed in ashes, as Jeremiah exhorted sinning Israel to do: "O daughter of my people .... wallow thyself in ashes" (Jer 6:26), or as Ezekiel in his lamentation for Tyre pictures her mariners as doing, crying bitterly and `casting up dust upon their heads and `wallowing themselves in the ashes (in their weeping for her whose head was lifted up and become corrupted because of her beauty), "in bitterness of soul with bitter mourning" (Ezek 27:30,31).
However, these and various other modes of expressing grief, repentance, and humiliation among the Hebrews, such as rending the garments, tearing the hair and the like, were not of Divine appointment, but were simply the natural outbursts of the impassioned oriental temperament, and are still customary among eastern peoples.
Figurative: The term "ashes" is often used to signify worthlessness, insignificance or evanescence (Gen 18:27; Job 30:19). "Proverbs of ashes," for instance, in Job 13:12, is Jobs equivalent, says one writer, for our modern "rot." For the ritual use of the ashes of the Red Heifer by the priests, see RED HEIFER.
George B. Eager