Exodus 7:14 says, And the LORD said unto Moses, Pharaoh’s heart is hardened, he refuseth to let the people go.  God told Moses of the hardness of Pharoah's heart.  We can believe this was because God caused Pharaoh to be that way, but I believe that Pharaoh was responsible for his attitude toward God, just as every person is.  Verse fifteen states, Get thee unto Pharaoh in the morning; lo, he goeth out unto the water; and thou shalt stand by the river’s brink against he come; and the rod which was turned to a serpent shalt thou take in thine hand.  God knew where Pharaoh was going to be the next morning, and told Moses to take the rod and meet Pharaoh at the river bank.   We need to be ready to go and witness to people today where they are when God sends us.  Verse sixteen adds, And thou shalt say unto him, The LORD God of the Hebrews hath sent me unto thee, saying, Let my people go, that they may serve me in the wilderness: and, behold, hitherto thou wouldest not hear.  God once again told Moses to tell Pharaoh that He was the LORD God of Israel and that He was once again telling Pharaoh to let His people go.  As long as God sends us to witness to a person, even if that person does not listen the first time, we should continue to go and witness to them.  Verse seventeen continues, 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.  God told Moses to tell Pharaoh that he would use the rod to turn the river into blood.  We have no such signs today, and people probably wouldn't believe them if we did.  People must simply come to God through faith in Christ as their Savior and Lord.  Verse eighteen concludes, And the fish that is in the river shall die, and the river shall stink; and the Egyptians shall lothe to drink of the water of the river.  Moses was to tell the Pharaoh of the result of the river being turned to blood.  The fish would die, the river would stink and no one would want to drink from the river.  Spiritually, if someone doesn't accept Christ today, that person is in the same situation.  Everything in the life of someone who does not accept Christ spiritually stinks.  Verse nineteen declares, And the LORD spake unto Moses, Say unto Aaron, Take thy rod, and stretch out thine hand upon the waters of Egypt, upon their streams, upon their rivers, and upon their ponds, and upon all their pools of water, that they may become blood; and that there may be blood throughout all the land of Egypt, both in vessels of wood, and in vessels of stone.  God told Moses to have Aaron to us the rod to turn all the water in Egypt to blood.  Verse twenty states, And Moses and Aaron did so, as the LORD commanded; and he lifted up the rod, and smote the waters that were in the river, in the sight of Pharaoh, and in the sight of his servants; and all the waters that were in the river were turned to blood.  Verse twenty-one adds, And the fish that was in the river died; and the river stank, and the Egyptians could not drink of the water of the river; and there was blood throughout all the land of Egypt.  Moses and Aaron did what God commanded and God did what He said He would do.  We can always be certain of the promises of God.  Verse twenty-two states, And the magicians of Egypt did so with their enchantments: and Pharaoh’s heart was hardened, neither did he hearken unto them; as the LORD had said.  We are told that the magicians of Egypt were able to duplicate turning the river into blood, but unless what Moses and Aaron did was just temporary, I am not sure how they were able to do so.  Anyway, it was enough that Pharaoh hardened his heart even further against God.  Though people in the world today may feel that they can do anything God can do, they can never bring salvation to themselves or the world.  Verse twenty-three adds, And Pharaoh turned and went into his house, neither did he set his heart to this also.  Pharaoh went back into his house, unconvinced by what Moses and Aaron had done.  Some people today are never going to be convinced that God is who He says He is.  Verse twenty-four states, And all the Egyptians digged round about the river for water to drink; for they could not drink of the water of the river.  Pharaoh was causing more work for the Israelites, and God was causing more work for the Egyptians.  Verse twenty-five concludes, And seven days were fulfilled, after that the LORD had smitten the river.  A week passed with the river still the same.  No matter how much time passes, those who reject Christ will be cut off from the Living Water.