“By this you shall know that I am the LORD: behold … I will strike the water that is in the Nile, and it shall turn into blood” (v17). The Nile was the source of prosperity and life for Egypt; in a relatively dry climate, the waters of this enormous river provided irrigation for fields as well as water for drinking, bathing, watering animals, etc. By striking the Nile, God was announcing His power over Egypt’s economy and also over the gods associated with the river.
“They could not drink the water of the Nile” (v24). Sometimes, God removes our “dependable” human resources so that we can see that He alone is the source of life.