Exodus 7:8-11

8Adonai told Moses and Aaron,

9“When Pharaoh speaks to you saying, ‘Prove yourselves with a miracle,’ then you are to say to Aaron, ‘Take your staff and cast it down before Pharaoh, so that it may become a serpent.’”

10So Moses and Aaron went in to Pharaoh and did as Adonai had commanded. Aaron threw down his staff before Pharaoh and before his servants, and it became a serpent.

11Then Pharaoh called for the wise men and the sorcerers, and they too, the magicians of Egypt, did the same with their secret arts.