Then the LORD said to Moses, "Say to Aaron, 'Stretch out your staff and strike the dust of the earth, so that it may become gnats in all the land of Egypt.'" And they did so. Aaron stretched out his hand with his staff and struck the dust of the earth, and there were gnats on man and beast. All the dust of the earth became gnats in all the land of Egypt. The magicians tried by their secret arts to produce gnats, but they could not. So there were gnats on man and beast. Then 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.
Exodus 8:16-19
The battle between the powers of evil and God continues and intensifies. We see the sinister effect of Pharaoh’s hardening of his own heart after the Spirit of God had begun to soften him, for now he is harder than ever. Part of the price of hardening one's heart is that it becomes harder than one realises. Sin is always something that passes beyond our power to control, He who commits it becomes the slave of it in the committal. This is what we see so frighteningly in these verses. The magicians are also on the side of the powers of darkness in this conflict, but they are tools, not principals, and they know it is time to call it a day, when they realise that their powers are spent in face of this vastly superior might and dominion with which they have been confronted. 'This is the finger of God' they exclaim in awe to the king, as if to say they knew when to retire from the unequal contest. It was wisdom for them to have thought so, and to have tried to persuade the king to do likewise, but he is no longer permitted to do so; the terrible 'No' which he uttered when he might have said 'Yes' becomes an awful and presently an unalterable reality for him, and the wheels of the chariot of divine justice come grinding inexorably towards him as he shuts himself up in the impenetrable prison of his own making. Let us learn from this grim story that to harden the heart against the word of God is to take a step towards a point of no return, the boundary between hope and despair.