Exodus 7:19-20

19 ADONAI said to Moshe, "Say to Aharon, 'Take your staff, reach out your hand over the waters of Egypt, over their rivers, canals, ponds and all their reservoirs, so that they can turn into blood. There will be blood throughout the whole land of Egypt, even in the wooden buckets and stone jars.'"
20 Moshe and Aharon did exactly what ADONAI had ordered. He raised the staff and, in the sight of Pharaoh and his servants, struck the water in the river; and all the water in the river was turned into blood.

Exodus 7:19-20 Meaning and Commentary

INTRODUCTION TO EXODUS 7

Moses and Aaron are ordered to go to Pharaoh, and require the dismission of the people of Israel, but they are told before hand that Pharaoh's heart would be hardened, and would refuse to let them go, until the hand of the Lord was stretched out, and great judgments were brought down upon, Egypt, and then they should come forth, Ex 7:1-5, which orders Moses and Aaron obeyed, and their age is observed, when this was done, Ex 7:6,7 and they are bid to work a miracle, when Pharaoh should demand one, by turning a rod into a serpent, which they did; but Pharaoh's magicians doing the same in appearance, his heart was hardened, Ex 7:8-14 and then they are directed to meet him at the river, and require the same as before; and if he refused, to smite the waters of the river with the rod, and turn them into blood, which they did, Ex 7:15-21, but Pharaoh's magicians doing the same by enchantments, he did not regard it, though the plague lasted seven days, Ex 7:22-25.

Complete Jewish Bible Copyright 1998 by David H. Stern. Published by Jewish New Testament Publications, Inc. All rights reserved. Used by permission.