Thy rod - Apparently the rod before described Exodus 4:2, which Moses on this occasion gives to Aaron as his representative.
A serpent - A word different from that in Exodus 4:3. Here a more general term, תנין tannı̂yn, is employed, which in other passages includes all sea or river monsters, and is more specially applied to the crocodile as a symbol of Egypt. It occurs in the Egyptian ritual, nearly in the same form, “Tanem,” as a synonym of the monster serpent which represents the principle of antagonism to light and life.