Aaron's rod, which was transformed into a serpent in the story in Exodus 7:8-13, represents the power of the Lord's teaching. This is because 'Aaron' represents doctrine and 'a rod' represents power.

Aaron demonstrated this power in front of Pharaoh. His rod-become-serpent swallowed the serpents of Pharaoh's magicians. This illustrates the power of the Lord's doctrine, taking power away from the falsity that Pharaoh represents.

In Exodus 7:12, Aaron's ROD signifies that the power of mere fallacies prevailed among the Egyptians. (Arcana Coelestia 9275)

(Notae: Arcana Coelestia 7287-7299)