“The Lord said to Moses: Say to Aaron: Extend your staff, and strike the dust of the earth, and it will become lice throughout the land of Egypt” (Exodus 8:12). “The Lord said to Moses: Say to Aaron: Extend your staff, and strike the dust of the earth” – Rabbi Tanḥum said: The Holy One blessed be He said to Moses: ‘It is not proper that the dust that protected you when you killed the Egyptian15See Exodus 2:12. will be stricken by you.’
Therefore, they were stricken with these three plagues by means of Aaron.16The first three plagues came from either the water or the dust, both of which had protected Moses in his youth. “They did so; and Aaron extended his hand with his staff, and struck the dust of the earth, and there were lice upon man, and upon beast; all the dust of the earth became lice throughout the land of Egypt” (Exodus 8:13).
“Aaron extended his hand with his staff” – why did He bring lice upon them? It is because they designated [the Israelites] as sweepers of the streets and the marketplaces; that is why their dust turned into lice. They would dig a square cubit but there was no dust there, as it is stated: “All the dust of the earth became lice.” “The magicians did so with their spells to bring out the lice, but they could not; and there were gnats upon man, and upon beast” (Exodus 8:14).
“The magicians did so with their spells to bring out the lice, but they could not” – Rabbi Elazar said: From here you learn that a demon is unable to create something smaller than a barley-bulk. The Rabbis say: They cannot even create something the size of a camel; rather, this it can gather and this it cannot gather.17If the item is smaller than a barley-bulk, the demons cannot even gather it from a different location.
“The magicians said to Pharaoh: It is the finger of God; but Pharaoh’s heart was hardened and he did not heed them, as the Lord had spoken” (Exodus 8:15). “The magicians said to Pharaoh: It is the finger of God” – when the magicians saw that they were unable to produce the lice, they were immediately aware that the actions were the actions of God and not the action of demons, and they no longer sought to compare themselves to Moses and produce the plagues.