The LORD God is unrelenting in His judgments.  He does not back down when people refuse to believe in Him.
  The plagues came from the LORD – Moses and Aaron did as the LORD told them.  The gods of Egypt were being judged.  Pharaoh’s hard heart of unbelief was being judged.

GNATS!
  The first insects sent as a plague were gnats throughout Egypt, on people and animals.  
Animals were now involved in the plagues sent by the LORD.  Another change in these miracles of judgment: the magicians of Egypt could not copy this miracle.  The magicians even told Pharaoh, “This is the finger of God.”  Exodus 8:16-18 
Nothing could change Pharaoh’s hard heart, nothing.

FLIES!
  Again the LORD sent Moses and Aaron to Pharaoh early the next morning and said what God wanted of Pharaoh: Let My people go to serve Me.  Pharaoh was warned of the plague of flies about to be unleashed on Egypt.  Flies carry disease and they are pests.  The LORD did another thing differently this time.  In the land of Goshen, where the Hebrew slaves lived, not one fly was present, only in the other areas of Egypt.

  Why did the LORD make this distinction?  So the Egyptians would know “that I, the LORD, am in the midst of the land.”  Pharaoh told Moses and Aaron, go sacrifice to your God, within the land of Egypt.  Moses said, we cannot do that.  What we sacrifice is an abomination (sheep) to the Egyptians.  They will stone us.  We must go three days’ journey into the wilderness and then sacrifice to Him as He commands us.  Pharaoh agreed!  You can sacrifice to your God, but not so far away.  Moses made supplication to the LORD for the flies to be removed.  They were.  But Pharaoh again went back on his word, hardened his heart and did not let the people go.  Exodus 8:16-32

God’s Word ~ Alive!

Surely, Pharaoh saw the hearts of Moses and Aaron
how they believed God and he did not.

Proverbs 12:20
“Deceit is in the heart of those
who devise evil,
But counselors of peace have joy.”