The following selection discusses what took place when Moses and Aaron first went before Pharaoh to petition him to let the Israelites out of his land. G‑d explains to Moses that Pharaoh would demand a sign. But when the Egyptian sorcerers were able to duplicate the miracle Moses and Aaron performed, he ignored them.

G‑d spoke to Moses and Aaron saying: "When Pharaoh speaks to you and he says, 'Give me a miraculous sign,' you shall say to Aaron, 'Take your staff and cast it down before Pharaoh. It will become a serpent.'" Moses and Aaron came to Pharaoh and they did as G‑d had commanded. Aaron threw his staff down before Pharaoh and his servants and it became a serpent. Pharaoh then summoned his scholars and sorcerers, and the Egyptian sorcerers were able to do the same thing with their incantations. Each one cast down his staff, and they became serpents; but the staff of Aaron then swallowed their staffs. (Ex. 7:8-12).

Moses' staff was holier…was engraved with the Holy Name in the upper Garden of Eden….

Why Aaron's staff and not Moses' staff? Because Moses' staff was holier since it was engraved with the Holy Name in the upper Garden of Eden.

Aaron's staff was a regular wooden staff, similar to those used as a walking stick. However, Moses' staff was one of the ten things created shortly before the onset of the Shabbat on the sixth day of Creation, according to the Mishna (Avot 5:6). Furthermore, it came from the upper Garden of Eden - the world of Beriya - and the 42 letter Name used in Creation was imbedded in it. Elsewhere, the Zohar explains that this staff was given to Moses by G‑d. (Zohar I, p. 6b)

The left is subdued by the right….

The Holy One blessed be He did not want to contaminate Moses' staff with the staffs of the sorcerers [that Aaron's staff would swallow up]. Furthermore, [Aaron's staff was used] because [the intention of this miraculous sign was] to subdue all those who derive from the left side [the severities of gevura], while Aaron derives from the right side [the aspect of chesed], and the left is subdued by the right.

Rabbi Chiya asked Rabbi Yose: Since it was known to the Holy One that the sorcerers would also turn their staffs into serpents, what mighty wonder was it [for Moses and Aaron] to do so before Pharaoh?

Rabbi Yose replied: This was where the thrashing he would receive had to begin [because] it was from the serpent that his sovereignty began.

This is as the verse states: Thus says the Lord G‑d, "I am against you, Pharaoh king of Egypt, the great serpent that crouches in its rivers and says, 'Mine is my river, and I have created myself'" (Isaiah 29:3). Technically, the "great serpent" here alludes to Arich Anpin of kelipa - the very highest level of the impure husks that obscure the G‑dliness which permeates the world. It is from this level that Pharaoh was nourished, and this is why G‑d wanted to strike him with Aaron's rod - to show that even a simple stick from the ordinary physical world could overpower the highest level of spiritual contamination - Arich Anpin of kelipa when this is G‑d's will. It is interesting to note that the Pharaohs of Egypt wore headdresses featuring a uraeus - a cobra in attack position, such as that depicted on the gold mask of Tutankhamun.

Now [when Pharaoh's sorcerers saw that Aaron's staff had turned into a serpent] they were delighted, for they possessed the knowledge of the serpent [i.e. the knowledge of the occult and black magic in which they were experts]. But when the serpent that Aaron's staff had become suddenly turned back into dry wood which then swallowed them [the sorcerers' staffs], they were startled, for they realized that there is a supernal power upon earth. [Until that moment] they believed that no other force had control [of the physical realm] other than themselves [and their occult powers].

This was the purpose of this sign, as the verse states, "And Egypt shall know that I am G‑d." (Ex. 7:5)

Then "the staff of Aaron swallowed their staffs". The staff of Aaron is stated specifically. It swallowed them when it turned back into wood.

Had Aaron's serpent swallowed the others, it could have been explained as a superior knowledge of occult powers. However, when a dry stick swallowed other dry sticks, this demonstrated that occult powers were not involved. Instead G‑d's ability to override the laws of nature and the physical world became revealed.

[Zohar II, p. 28a; based on Ohr Yakar; translation and commentary by Moshe Miller]