Ashes - Vine's Expository Dictionary of New Testament Words
Ashes[ A-1,Noun,G4700, spodos ]
ashes," is found three times, twice in association with sackcloth, Matthew 11:21; Luke 10:13, as tokens of grief (cp. Esther 4:1, Esther 4:3; Isaiah 58:5; Isaiah 61:3; Jeremiah 6:26; Jonah 3:6); of the ashes resulting from animal sacrifices, Hebrews 9:13; in the OT, metaphorically, of one who describes himself as dust and "ashes," Genesis 18:27, etc.
[ B-1,Verb,G5077, tephroo ]
"to turn to ashes," is found in 2 Peter 2:6, with reference to the destruction of Sodom and Gomorrah.
(1) Tephra, frequently used of the "ashes" of a funeral pile, is not found in the NT.
(2) The Hebrew verb, rendered "accept" in Psalms 20:3, "accept thy burnt sacrifice," signifies "to turn to ashes" (i.e., by sending fire from heaven). See also Exodus 27:3; Numbers 4:13, "shall take away the ashes."