Albert Barnes Commentary Jeremiah 10:14

"Every man is become brutish [and is] without knowledge; every goldsmith is put to shame by his graven image; for his molten image is falsehood, and there is no breath in them." — Jeremiah 10:14 (ASV)

In his knowledge - Rather, without knowledge; i.e., on comparing his powerless idols with the awe-inspiring grandeur of a tropical thunderstorm, the man who can still worship them instead of the Creator is destitute of knowledge.

Every founder ... - Or, every goldsmith is put to shame etc. He has exhausted his skill on what remains an image.