Exodus 7:6-10

So Moses and Aaron did this; as the Lord commanded them, so they did.

And Moses was eighty years old and Aaron eighty-three, when they spoke to Pharaoh. Aaron’s Staff Turns into a Serpent

Now the Lord spoke to Moses and Aaron, saying,

“When Pharaoh speaks to you, saying, ‘Work a miracle,’ then you shall say to Aaron, ‘Take your staff and throw it down before Pharaoh, so that it may turn into a serpent.’ ”

So Moses and Aaron came to Pharaoh, and so they did, just as the Lord had commanded; and Aaron threw his staff down before Pharaoh and his servants, and it turned into a serpent.