Exodus 7:6-11
English Standard Version
Chapter 7
6Moses and Aaron did so; they did just as the Lord commanded them. 7Now Moses was eighty years old, and Aaron eighty-three years old, when they spoke to Pharaoh.
8Then the Lord said to Moses and Aaron,
9"When Pharaoh says to you, ‘Prove yourselves by working a miracle,’ then you shall say to Aaron, ‘Take your staff and cast it down before Pharaoh, that it may become a serpent.’"
10So Moses and Aaron went to Pharaoh and did just as the Lord commanded. Aaron cast down his staff before Pharaoh and his servants, and it became a serpent.
11Then Pharaoh summoned the wise men and the sorcerers, and they, the magicians of Egypt, also did the same by their secret arts.
