Exodus 7:12-14

New Revised Standard Version, Anglicised Catholic Edition

¹² Each one threw down his staff, and they became snakes; but Aaron’s staff swallowed up theirs. 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.