Coals

Vine's Expository Dictionary of NT Words

1: Ἄνθραξ (Strong'S #440 — Adjective — antrax — anth'-rax )

"a burning coal" (cp. Eng., "anthracite,") is used in the plural in  Romans 12:20 , metaphorically in a proverbial expression, "thou shalt heap coals of fire on his head" (from  Proverbs 25:22 ), signifying retribution by kindness, i.e., that, by conferring a favor on your enemy, you recall the wrong he has done to you, so that he repents, with pain of heart.

2: Ἀνθρακιά (Strong'S #439 — Noun Feminine — anthrakia — anth-rak-ee-ah' )

akin to No. 1, is "a heap of burning coals, or a charcoal fire,"  John 18:18;  21:9 .

Hastings' Dictionary of the New Testament

(ἄνθρακες, prumae )

The coal of the Bible is charcoal. The knowledge of the process of preparing charcoal from timber dates from a remote period. True coal is not found in Syria except in one part of Lebanon, where it was mined for a short time about 1834 (C. R. Conder, Tent Work in Pal. , London, 1878, ii. 326). Pieces of charcoal in process of combustion were called ‘coals of fire’ (ἄνθρακες πυρός = גַּחֲלֵי אֵשׁ), and glowing coals heaped upon the head became a figure for the burning sense of shame which an enemy feels when he receives a return of good for the evil he has done ( Romans 12:20 ||  Proverbs 25:21-22). Another view (held by Chrysostom, Theodoret, Grotius, etc.), that the ‘coals of fire’ are Divine judgments which will fall on the sinner’s head if he hardens his heart against persevering love, is impossible. Benevolence tainted by such a thought is scarcely better than malevolence. Jerome says rightly: ‘ “Carbones ignis congregabis super caput eius,” non in maledictum et condemnationem, ut plerique existimant, sed in correctionem et poenitudinem’ ( contra Pelagianos , i. 30; cf. Meyer, Romans , ii. [1874] 272).

James Strahan.