Exodus 7:13-15

New Revised Standard Version, Anglicised

¹³ Still Pharaoh’s heart was hardened, and he would not listen to them, as the Lord had said.

The First Plague: Water Turned to Blood

¹⁴ Then the Lord said to Moses, ‘Pharaoh’s heart is hardened; he refuses to let the people go. ¹⁵ Go to Pharaoh in the morning, as he is going out to the water; stand by at the river bank to meet him, and take in your hand the staff that was turned into a snake.