16Then say to him, ‘The LORD, the God of the Hebrews, has sent me to tell you: Let My people go, so that they may worship Me in the wilderness. But you have not listened until now.
17This is what the LORD says: By this you will know that I am the LORD. Behold, with the staff in my hand I will strike the water of the Nile, and it will turn to blood.
— Exodus 7:16-17