"And
the LORD spake unto Moses and unto Aaron, saying, When Pharaoh
shall speak unto you, saying, Shew a miracle for you: then thou
shalt say unto Aaron, Take thy rod, and cast it before Pharaoh,
and it shall become a serpent. And Moses and Aaron went in unto
Pharaoh, and they did so as the LORD had commanded: and Aaron
cast down his rod before Pharaoh, and before his servants, and
it became a serpent. Then Pharaoh also called the wise men and
the sorcerers: now the magicians of Egypt, they also did in like
manner with their enchantments. For they cast down every man his
rod, and they became serpents: but Aaron's rod swallowed up their
rods" (Exodus 7:8-12).