10And Moses and Aaron went in unto Pharaoh, and they did so, as Jehovah had commanded: and Aaron cast down his rod before Pharaoh and before his servants, and it became a serpent. 11Then Pharaoh also called for the wise men and the sorcerers: and they also, the magicians of Egypt, did in like manner with their enchantments. 12For they cast down every man his rod, and they became serpents: but Aaron’s rod swallowed up their rods. 13And Pharaoh’s heart was hardened, and he hearkened not unto them; as Jehovah had spoken.

14And Jehovah said unto Moses, Pharaoh’s heart is stubborn, he refuseth to let the people go. 15Get thee unto Pharaoh in the morning; lo, he goeth out unto the water; and thou shalt stand by the river’s brink to meet him; and the rod which was turned to a serpent shalt thou take in thy hand. 16And thou shalt say unto him, Jehovah, the God of the Hebrews, hath sent me unto thee, saying, Let my people go, that they may serve me in the wilderness: and, behold, hitherto thou hast not hearkened. 17Thus saith Jehovah, In this thou shalt know that I am Jehovah: behold, I will smite with the rod that is in my hand upon the waters which are in the river, and they shall be turned to blood.