As when the melting fire burneth... — Better, as when fire Kindleth brushwood, as when fire causeth the water to boil. The two-fold action of material fire is used, as elsewhere, as a symbol of the “consuming fire” (Hebrews 12:29) of the wrath of Jehovah.
Related Commentaries of Isaiah 64:2
Isaiah 64:2
2 As when the meltinga fire burneth, the fire causeth the waters to boil, to make thy name known to thine adversaries, that the nations may tremble at thy presence!