Exodus 7:7 WBT

⁵  And the Egyptians shall know that I [am] the LORD, when I stretch forth my hand upon Egypt, and bring out the children of Israel from among them.

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

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

⁸  And the LORD spoke to Moses, and to Aaron, saying,

⁹  When Pharaoh shall speak to you, saying, Show a miracle for you: then thou shalt say to Aaron, Take thy rod, and cast [it] before Pharaoh, [and] it shall become a serpent.