Cross reference
Exodus 9:8
8 And Jehovah saith unto Moses and unto Aaron, `Take to you the fulness of your hands `of' soot of a furnace, and Moses hath sprinkled it towards the heavens, before the eyes of Pharaoh,
Exodus 8:16
16 And Jehovah saith unto Moses, `Say unto Aaron, Stretch out thy rod, and smite the dust of the land, and it hath become gnats in all the land of Egypt.'