The Hebrew word rendered "serpent" in Genesis 3:1 is Nachash (from the root Nachash, to shine, and means a shinning one.

Hence, in Chaldee it means brass or copper, because of its shining. Hence also, the word Nehushtan, a piece of brass, in 2Kings 18:4.

In the same way Saraph, in Isaiah 6:2,6, means a burning one, and, because the serpents mentioned in Numbers 21 were burning, in the poison of their bite, they were called Saraphim, or Seraphs.

But when the LORD said unto Moses, "Make thee a fiery serpent" (Numbers 21:8), He said, "Make thee a Saraph", and, in obeying this command, we read in verse 9, "Moses made a Nachash of brass". Nachash is thus used as being interchangeable with Saraph.

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