Exodus 8:16-19

16Then the Lord said to Moses, “Tell Aaron, ‘Hold out your staff and strike the dust on the ground. All over Egypt the dust will turn into gnats.’ ”

17When Moses told him, Aaron held out the staff in his hand and struck the dust on the ground. It turned into gnats that bit people and animals. All the dust on the ground everywhere in Egypt turned into gnats.

18The magicians also tried to produce gnats using their magic spells, but they couldn’t do it. The gnats bit people and animals.

19So the magicians said to Pharaoh, “This is the hand of God!” Yet, Pharaoh continued to be stubborn and would not listen to Moses and Aaron, as the Lord had predicted.