(17) In this thou shalt know that I am the Lord.—See the comment on Exodus 7:5.

The rod that is in my hand, i.e., “in the hand of my servant.” God is here represented as about to do that which was actually done by Aaron (Exodus 7:20). “Qui facit per alium, facit per se.”

7:14-25 Here is the first of the ten plagues, the turning of the water into blood. It was a dreadful plague. The sight of such vast rolling streams of blood could not but strike horror. Nothing is more common than water: so wisely has Providence ordered it, and so kindly, that what is so needful and serviceable to the comfort of human life, should be cheap and almost every where to be had; but now the Egyptians must either drink blood, or die for thirst. Egypt was a pleasant land, but the dead fish and blood now rendered it very unpleasant. It was a righteous plague, and justly sent upon the Egyptians; for Nile, the river of Egypt, was their idol. That creature which we idolize, God justly takes from us, or makes bitter to us. They had stained the river with the blood of the Hebrews' children, and now God made that river all blood. Never any thirsted after blood, but sooner or later they had enough of it. It was a significant plague; Egypt had great dependence upon their river, Zec 14:18; so that in smiting the river, they were warned of the destruction of all the produce of their country. The love of Christ to his disciples changes all their common mercies into spiritual blessings; the anger of God towards his enemies, renders their most valued advantages a curse and a misery to them. Aaron is to summon the plague by smiting the river with his rod. It was done in the sight of Pharaoh and his attendants, for God's true miracles were not performed as Satan's lying wonders; truth seeks no corners. See the almighty power of God. Every creature is that to us which he makes it to be water or blood. See what changes we may meet with in the things of this world; what is always vain, may soon become vexatious. See what mischievous work sin makes. If the things that have been our comforts prove our crosses, we must thank ourselves. It is sin that turns our waters into blood. The plague continued seven days; and in all that time Pharaoh's proud heart would not let him desire Moses to pray for the removal of it. Thus the hypocrites in heart heap up wrath. No wonder that God's anger is not turned away, but that his hand is stretched out still.Turned to blood - This miracle would bear a certain resemblance to natural phenomena, and therefore be one which Pharaoh might see with amazement and dismay, yet without complete conviction. It is well known that before the rise the water of the Nile is green and unfit to drink. About the 25th of June it becomes clear, and then yellow, and gradually reddish like ochre; an effect due to the presence of microscopic cryptogams and infusoria. The supernatural character of the visitation was tested by the suddenness of the change, by its immediate connection with the words and act of Moses, and by its effects. It killed the fish, and made the water unfit for use, neither of which results follows the annual discoloration. 17-21. Aaron lifted up the rod and smote the waters, &c.—Whether the water was changed into real blood, or only the appearance of it (and Omnipotence could effect the one as easily as the other), this was a severe calamity. How great must have been the disappointment and disgust throughout the land when the river became of a blood red color, of which they had a national abhorrence; their favorite beverage became a nauseous draught, and the fish, which formed so large an article of food, were destroyed. [See on [17]Nu 11:5.] The immense scale on which the plague was inflicted is seen by its extending to "the streams," or branches of the Nile—to the "rivers," the canals, the "ponds" and "pools," that which is left after an overflow, the reservoirs, and the many domestic vessels in which the Nile water was kept to filter. And accordingly the sufferings of the people from thirst must have been severe. Nothing could more humble the pride of Egypt than this dishonor brought on their national god. Because thou saidst, Who is the Lord? and, I know not the Lord, Exodus 5:2, thou shalt know him experimentally, and to thy cost. Behold, I will smite, viz. by Aaron’s hand, who shall do it by my command and direction. Thus Pilate is said to give Christ’s body to Joseph, Mark 15:45, because he commanded it to be delivered by others to him. The same action is ascribed to the principal and instrumental cause. The river Nile, which was one of their principal gods; and therefore it was inexcusable in them, that they would not renounce those feeble gods, which were unable to help not only their worshippers, but even themselves, nor embrace the service and commands of that God whose almighty power they saw and felt.

They shall be turned to blood, which was a very grievous plague to them; both because it was an eternal dishonour to their religion, and because from hence they had both their drink, Deu 11:10,11 Jer 2:18, and their meat, Numbers 11:5; for greater and lesser cattle they would not eat, Exodus 8:26. And it was a very proper punishment for them, who had made that river an instrument for the execution of their bloody design against the Israelitish infants, Exodus 1:22.

Thus saith the Lord, in this thou shalt know that I am the Lord,.... By the following instance of his power and vengeance:

behold, I will smite with the rod that is in my hand; which though in the hand of Moses, Exodus 7:18 yet he being his ambassador, and representing him, is said to be in the hand of the Lord; and with this he threatens to smite

upon the waters which are in the river; the river Nile, and the canals thereof:

and they shall be turned to blood; and if this river was their god, it would abundantly appear that the God of the Hebrews was Jehovah, and above all gods, and particularly above theirs.

Thus saith the LORD, In this thou shalt know that I am the LORD: behold, I will smite with the rod that is in mine hand upon the waters which are in the river, and they shall be turned to blood.