Q. I’m an artist doing research for my thesis on angels and apsaras. Where does the snake image of seraphs and other bull-like angelic creatures come from?
A. The image of the seraph as a snake probably comes from Egyptian art. (The term ‘seraph’ means both fiery and snake; the idea is probably that the snake’s venom is fiery, i.e., the victim of a snake bit feels a burning sensation) There are eighth century B.C.E. stamp seals from ancient Judah that portray the seraph, and the image is similar to a snake common in Egyptian art of that era and earlier.
Here you can see drawings some of these seals from Othmar Keel and Christoph Uehlinger, Gods, Goddesses and Images of God in Ancient Israel (Fortress Press, 1998). I also include a drawing of a similar snake or asp from an Egyptian headdress. As Keel and Uehlinger point out throughout their book, Egyptian art had a very strong influence on Judean and Israelite art.
Incidentally, seals 273 and 274a are especially interesting. Seal 273 portrays Yhwh symbolically as a sun disk wearing a crown (a typical representation in Israelite-Judean art). Yhwh is thus portrayed as king, and surrounding him are the seraphs. Seal 274a may portray Yhwh as king, sitting on some sort of structure or throne, also attended by a seraph, this time a seraph with wings.
These seals picture basically the same scene portrayed by Isaiah in the opening verses