Moses and Aaron appear before Pharaoh and command him to allow the people of Israel to leave Egypt. When Pharaoh refuses, Moses strikes the water of the Nile with his staff, and the water of the Nile turns into blood.
BibleGateway: Exodus 7 ESV Text: Exodus 7 KJV Text: Exodus 7:1-25 KJV Text (alt. audio): Chapter 7: 1 And the LORD said unto Moses, See, I have made thee a god to Pharaoh: and Aaron… Moses and Aaron appear before Pharaoh and command him to allow the people of Israel to leave Egypt. When Pharaoh refuses, Moses strikes the water of the Nile with his staff, and the water of the Nile turns into blood.