Exodus 7:17

“And you shall take in your hand this staff, with which you shall do the signs.”

“Then the Egyptians shall know that I am Yahweh, when I stretch out My hand against Egypt and bring out the sons of Israel from their midst.”

and that you may recount in the hearing of your son and of your grandson, how I dealt severely with the Egyptians, and how I put My signs among them, that you may know that I am Yahweh.”

and His signs and His works which He did in the midst of Egypt to Pharaoh the king of Egypt and to all his land;

He permitted no man to oppress them, And He reproved kings for their sakes,

“Then You performed signs and wonders against Pharaoh, Against all his servants and all the people of his land; For You knew that they acted presumptuously toward them, And made a name for Yourself as it is this day.

“I will also make the land drink the discharge of your blood As far as the mountains, And the ravines will be full of you.

And the second angel sounded, and something like a great mountain burning with fire was thrown into the sea; and a third of the sea became blood,

These have the authority to shut up the sky, so that rain will not fall during the days of their prophesying; they also have authority over the waters to turn them into blood, and to strike the earth with every plague, as often as they wish.

And the second angel poured out his bowl into the sea, and it became blood like that of a dead man, and every living thing in the sea died.

Then the third angel poured out his bowl into the rivers and the springs of waters, and they became blood.