Isaiah 41:7 (BSB)

The craftsman encourages the goldsmith, and he who wields the hammer cheers him who strikes the anvil, saying of the welding, “It is good.” He nails it down so it will not be toppled.

From Isaiah 41. Also in the ESV.

Commentary on Isaiah 41:7

• John Calvin (Reformed), Calvin's Commentaries on Isaiah 41:7: 7. The workmen encouraged the founder. This verse is explained in various ways, and indeed is somewhat obscure; and even the Jewish writers are not agreed as to the meaning of the words. I see no reason why חרש (cherish) should be here understood to mean simply a carpenter, for it means any kind of workman.
• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Isaiah 41:1-9: That particular instance of God's care for his people Israel in raising up Cyrus to be their deliverer is here insisted upon as a great proof both of his sovereignty above all idols and of his power to protect his people. Here is, I. A general challenge to the worshippers and admirers of idols to make good their pretensions, in competition with God and opposition to him, Isa 41:1.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Isaiah 41:7: So the carpenter encouraged the goldsmith,.... The carpenter, when he had made a wooden image, encouraged and hastened the goldsmith, or the "finer", as some render it, to do his part, in covering it with plates of gold or silver: and he that smootheth with the hammer him that smote the anvil; he that beat out thin plates of gold and silver with the hammer...
• Jamieson-Fausset-Brown (Reformed), Commentary Critical and Explanatory on the Whole Bible on Isaiah 41:7: One workman encourages the other to be quick in finishing the idol, so as to avert the impending danger. nails--to keep it steady in its place. Wisdom 13:15, 16, gives a similar picture of the folly of idolatry.