ChristianAnswers.Net WebBible Encyclopedia
Two different words are found in Hebrew to denote coal, both occurring in Proverbs 26:21, “As coal [Hebrew: peham; i.e., ‘black coal’] is to burning coal [Hebrew: gehalim].” The latter of these words is used in Job 41:21; Proverbs 6:28; Isaiah 44:19.
The words “live coal” in Isaiah 6:6 are more correctly “glowing stone.”
In Lam. 4:8 the expression “blacker than a coal” is literally rendered in the margin of the Revised King James Version “darker than blackness.”
“Heaping coals of fire on the head” symbolizes overcoming evil with good. The words of Paul (Romans 12:20) are equivalent to saying, “By charity and kindness thou shalt soften down his enmity as surely as heaping coals on the fire fuses the metal in the crucible.”