Exodus:8:30-32
kjv@Exodus:8:30 @ And Moses went out from Pharaoh, and intreated the LORD.
kjv@Exodus:8:31 @ And the LORD did according to the word of Moses; and he removed the swarms of flies from Pharaoh, from his servants, and from his people; there remained not one.
kjv@Exodus:8:32 @ And Pharaoh hardened his heart at this time also, neither would he let the people go.