Exodus 7:19

7:19 Then the Lord said to Moses, “Tell Aaron, ‘Take your staff and stretch out your hand over Egypt’s waters – over their rivers, over their canals, over their ponds, and over all their reservoirs – so that it becomes blood.’ There will be blood everywhere in the land of Egypt, even in wooden and stone containers.”

Exodus 8:1

8:1 (7:26) Then the Lord said to Moses, “Go to Pharaoh and tell him, ‘Thus says the Lord: “Release my people in order that they may serve me!