John Gill Commentary Isaiah 40:19

"The image, a workman hath cast [it], and the goldsmith overlayeth it with gold, and casteth [for it] silver chains." — Isaiah 40:19 (ASV)

The workman melts a graven image Or, "the founder"; he melts some sort of metal, as iron, brass, copper, or lead, which he casts into a mould for an image, and afterwards engraves, or has it engraved: and the goldsmith spreads it over with gold; or, "the finer"; he stretches out plates of gold, and covers it with them, so that it looks as if it was made of solid gold, and deceives the eyes of men; such stupidity and vanity are there in mortals to believe that there can be deity in such a piece of workmanship! and casts silver chains to put about the graven image, either for ornament, or rather to fasten it to some wall or pillar, that it may stand upright, and may not be taken down and stolen away, or blown down with the wind, or fall of itself and be broken; thus ridiculing the weakness of these idols, and the folly of the makers and worshippers of them. The Targum is, "the silversmith joins silver chains to it."