The third plague, gnats, is the first that the Egyptian magicians cannot replicate and they conclude that it is the finger of God.
Any of the first nine plagues could be used as an entry point into this plot line in the book of Exodus. Beginning interpreters of Exodus will encounter discussions of the relationship between various plagues and natural occurrences in the Egyptian environment. At times the attempts to find correlations are an effort to explain in rational terms what in the text is celebrated as the deed of God. At other times the attempts seek to preserve the integrity of nature. Still others are seeking ways to view the plagues as the understandable consequences of human action; natural evils are, in some measure, considered to be the consequences of social evils. These efforts either seek to reduce the disruptiveness of divine intervention or to tightly intertwine God's action with natural occurrences. Many aspects of the discussion of miracles in the New Testament are paralleled in the history of interpretation of the plagues. In addition, discussions of the plagues intersect with considerations of hardening Pharaoh's heart. Theories of divine causation and human accountability are inescapably involved in the interpretation of the plagues.
In the specific plague of gnats, the Egyptian magicians are quoted as saying the deed was the "finger of God" at work (8:19). In the narrative, the magicians were able to replicate the first two plagues, but the third, involving gnats, was beyond their ability. Overall, the plagues are celebrated in Israel as the "signs and wonders" of God directed against Egypt to bring about the release of Israel from Egypt. They are part of the outstretched arm of God operating against Egypt with the climactic act being the death of Pharaoh and his army in the sea. The presentation of the plague accounts is quite patterned. There are three sets of three plagues. Three times Moses and Aaron are to position themselves in the morning before Pharaoh (7:15; 8:20; 9:13) to forewarn him of the pending plague. Without time reference, three times they are commanded to go to Pharaoh with a warning (8:1-2; 9:1-2; 10:1). In the remaining three there is no warning. Interspersed in this patterning is the resistance of Pharaoh, sometimes with a relenting that is quickly withdrawn when the plague passes. Repeatedly, Israel is explicitly exempted from the plagues.
The protracted narrative heightens the distinctiveness of Israel as the cherished people of God. The protracted conflict with Pharaoh heightens the wonderment that Israel experiences in its eventual deliverance. This was no small matter. The opposition was formidable and entrenched. Their deliverance could only be understood as the mighty act of God. In the end, the narrative is not interested in explanations of causality; it all drives toward the doxology in Exodus 15. The Lord has triumphed gloriously. Singing comes before and after interpretative explanations.
16 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 throughout the whole land of Egypt. 17And they did so; Aaron stretched out his hand with his staff and struck the dust of the earth, and gnats came on humans and animals alike; all the dust of the earth turned into gnats throughout the whole land of Egypt. 18The magicians tried to produce gnats by their secret arts, but they could not. There were gnats on both humans and animals. 19And the magicians said to Pharaoh, This is the finger of God! But Pharaohs heart was hardened, and he would not listen to them, just as the Lord had said.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org