12 So Moses and Aaron went out from Pharaoh; and Moses cried to the Lord concerning the frogs, as he had agreed with Pharaoh. 13 And the Lord did according to the word of Moses; the frogs died out of the houses and courtyards and out of the fields. 14 And they gathered them together in heaps, and the land stank. 15 But when Pharaoh saw that there was a respite, he hardened his heart, and would not listen to them; as the Lord had said.
16 Then the Lord said to Moses, "Say to Aaron, 'Stretch out your rod and strike the dust of the earth, that it may become gnats throughout all the land of Egypt.'" 17 And they did so; Aaron stretched out his hand with his rod, and struck the dust of the earth, and there came gnats on man and beast; all the dust of the earth became gnats throughout all the land of Egypt. 18 The magicians tried by their secret arts to bring forth gnats, but they could not. So there were gnats on man and beast. 19 And the magicians said to Pharaoh, "This is the finger of God." But Pharaoh's heart was hardened, and he would not listen to them; as the Lord had said.
Matthew Henry's Commentary on Exodus 8:12-19
Commentary on Exodus 8:1-15
(Read Exodus 8:1-15)
Pharaoh is plagued with frogs; their vast numbers made them sore plagues to the Egyptians. God could have plagued Egypt with lions, or bears, or wolves, or with birds of prey, but he chose to do it by these despicable creatures. God, when he pleases, can arm the smallest parts of the creation against us. He thereby humbled Pharaoh. They should neither eat, nor drink, nor sleep in quiet; but wherever they were, they should be troubled by the frogs. God's curse upon a man will pursue him wherever he goes, and lie heavy upon him whatever he does. Pharaoh gave way under this plague. He promises that he will let the people go. Those who bid defiance to God and prayer, first or last, will be made to see their need of both. But when Pharaoh saw there was respite, he hardened his heart. Till the heart is renewed by the grace of God, the thoughts made by affliction do not abide; the convictions wear off, and the promises that were given are forgotten. Till the state of the air is changed, what thaws in the sun will freeze again in the shade.
Commentary on Exodus 8:16-19
(Read Exodus 8:16-19)
These lice were produced out of the dust of the earth; out of any part of the creation God can fetch a scourge, with which to correct those who rebel against him. Even the dust of the earth obeys him. These lice were very troublesome, as well as disgraceful to the Egyptians, whose priests were obliged to take much pains that no vermin ever should be found about them. All the plagues inflicted on the Egyptians, had reference to their national crimes, or were rendered particularly severe by their customs. The magicians attempted to imitate it, but they could not. It forced them to confess, This is the finger of God! The check and restraint put upon us, must needs be from a Divine power. Sooner or later God will force even his enemies to acknowledge his own power. Pharaoh, notwithstanding this, was more and more obstinate.