And the LORD said to Moses, “Say to Aaron, ‘Take your staff and stretch out your hand over the waters of Egypt, over their rivers, their canals, and their ponds, and all their pools of water, so that they may become blood, and there shall be blood throughout all the land of Egypt, even in vessels of wood and in vessels of stone.’”
19. And the Lord spake unto Moses. This is the more extended narrative of which I spoke; for Moses mentions nothing different from what went before, but explains more distinctly his mode of action in the performance of the miracle, namely, that what God had commanded was completed by the instrumentality of Aaron.
Water turned to blood strikes horror into the soul, but the justice runs deeper: Egypt made an idol of the Nile, and God justly turned their god into a curse. Whatever creature we worship instead of the Creator, the Lord will either remove from us or make bitter to our taste.
AI summary
Commenting on Exodus 7:14-25
And the Lord spake unto Moses,.... Pharaoh still being obstinate, and refusing to let the people go: say unto Aaron, take thy rod, and stretch out thine hand upon the waters of Egypt; upon all of them in general, what were in the river Nile, or derived from it, as follows: upon their streams; the seven streams of the river Nile; see Gill on Isa 11:15.