Exodus 7:10

6Moses and Aaron did so. As the LORD commanded them, so they did.

7Moses was eighty years old, and Aaron eighty-three years old, when they spoke to Pharaoh.

8The LORD spoke to Moses and to Aaron, saying,

9“When Pharaoh speaks to you, saying, ‘Perform a miracle!’ then you shall tell Aaron, ‘Take your rod, and cast it down before Pharaoh, and it will become a serpent.’”

10Moses and Aaron went in to Pharaoh, and they did so, as the LORD had commanded. Aaron cast down his rod before Pharaoh and before his servants, and it became a serpent.

11Then Pharaoh also called for the wise men and the sorcerers. They also, the magicians of Egypt, did the same thing with their enchantments.

12For they each cast down their rods, and they became serpents; but Aaron’s rod swallowed up their rods.

13Pharaoh’s heart was hardened, and he didn’t listen to them, as the LORD had spoken.

14The LORD said to Moses, “Pharaoh’s heart is stubborn. He refuses to let the people go.