Has the wonder of Moses and Aaron been trumped or perhaps equaled by the wonder of the magicians? And does that mean the message of liberation is out of sight now? No, for Aaron’s staff devours all the other staffs. It does not say that the serpent devoured the other serpents, but the staff. This is about the staff of God (Exodus 4:20b) which punishes the magicians’ staffs.
The devouring is a taste of the ten plagues to come.
Pharaoh thinks that all of Egypt is in his godly power, including Israel in Egypt. He guarantees the order of things. He has life and death at his disposal.
But his power is devoured. God will disrupt his world with ten plagues. This is how God will show (the power of) his Word. He will deliver his people from slavery (Exodus 3:8; Exodus 6:6).
God liberates through his judgment. Why is judgment needed? Because his opponent (Pharaoh) will not let the slaves go free just like that. With the plagues, the Lord forces Pharaoh to let his people go, but the final demise of Pharaoh happens in the Red Sea. God liberates his people by his judgment over Pharaoh.
In Exodus 15:4–5, we read that Pharaoh’s army is destroyed in the waters of the Red Sea. Here, with Moses, we already taste this destruction through the staffs that are swallowed up.
12 For each man cast down his staff, and they became serpents. But Aaron’s staff swallowed up their staffs.