Exodus 7:17
King James Version
“Thus saith the LORD, In this thou shalt know that I the LORD: behold, I will smite with the rod that in mine hand upon the waters which in the river, and they shall be turned to blood.”
Context
14And the LORD said unto Moses, Pharaoh’s heart hardened, 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 against he come; and the rod which was turned to a serpent shalt thou take in thine hand.
16And thou shalt say unto him, The LORD 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 wouldest not hear.
17Thus saith the LORD, In this thou shalt know that I the LORD: behold, I will smite with the rod that in mine hand upon the waters which in the river, and they shall be turned to blood.
18And the fish that in the river shall die, and the river shall stink; and the Egyptians shall lothe to drink of the water of the river.
19And the LORD spake unto Moses, Say unto Aaron, Take thy rod, and stretch out thine hand upon the waters of Egypt, upon their streams, upon their rivers, and upon their ponds, and upon all their pools of water, that they may become blood; and there may be blood throughout all the land of Egypt, both in wood, and in stone.
20And Moses and Aaron did so, as the LORD commanded; and he lifted up the rod, and smote the waters that in the river, in the sight of Pharaoh, and in the sight of his servants; and all the waters that in the river were turned to blood.