What does Exodus 7:18 mean?
Through Moses (Exodus 7:14–15), the Lord is declaring a judgment on Egypt and its stubborn ruler, Pharaoh (Exodus 7:16). God will turn the water of the Nile river into blood, as a way of proving his power and authority. This will result in exactly the sort of consequences one would expect. Blood decomposes. Fish cannot breathe blood. The entire Nile system will become a reeking, rotting sludge. This would also apply to all the surface waters and reservoirs of the land (Exodus 7:19).Crops cannot survive without water—and neither can people. This explains the comment about how the Egyptians will "grow weary" of the situation. This applies a Hebrew root word implying struggle, frustration, exhaustion, and impatience. To live (Exodus 7:25), Egyptians will be forced to dig for underground springs and pools (Exodus 7:24). This is a not-so-subtle response to Pharaoh's earlier cruelty. When first refusing to release the Israelites (Exodus 5:4), Pharaoh spitefully made their work even harder (Exodus 5:6–9). He forced them to search for something which had once been provided (Exodus 5:10–12). Now, the people of Egypt will be forced into harsh, desperate labor to replace the water which was once so easy to find. Further, the river where Hebrew children were slaughtered (Exodus 1:22) now brings blood back to Egypt.