Most people are familiar with the biblical stories of the golden calf and the bronze serpent . What few understand, however, is why the golden calf was condemned as an idol (פסל), while the bronze serpent wasn’t.

In both cases, Aaron and Moses, respectively, cast images of animals. One made of gold and the other made of bronze (or copper). But didn’t God explicitly command that “You shall not make for yourself a carved image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth”?

Nevertheless, the serpent cast by Moses is regarded positively, while the calf cast by Aaron is condemned as sinful. Both were statues and images of animals, but the Bible sees idolatry in the golden calf and divine healing in the bronze snake. The biblical bronze serpent wrapped around a staff is believed to be one of the inspirations behind many modern medical and pharmaceutical logos featuring a similar motif.

But as we shall see, the Bible records that some...