Exodus 7:7-9

Living Bible

⁷ Moses was eighty years old and Aaron eighty-three at this time of their confrontation with Pharaoh.

⁸ Then the Lord said to Moses and Aaron, ⁹ “Pharaoh will demand that you show him a miracle to prove that God has sent you; when he does, Aaron is to throw down his rod, and it will become a serpent.”