Exodus 9:10

6The LORD did that thing on the next day; and all the livestock of Egypt died, but of the livestock of the children of Israel, not one died.

7Pharaoh sent, and, behold, there was not so much as one of the livestock of the Israelites dead. But the heart of Pharaoh was stubborn, and he didn’t let the people go.

8The LORD said to Moses and to Aaron, “Take handfuls of ashes of the furnace, and let Moses sprinkle it toward the sky in the sight of Pharaoh.

9It shall become small dust over all the land of Egypt, and shall be boils and blisters breaking out on man and on animal, throughout all the land of Egypt.”

10They took ashes of the furnace, and stood before Pharaoh; and Moses sprinkled it up toward the sky; and it became boils and blisters breaking out on man and on animal.

11The magicians couldn’t stand before Moses because of the boils; for the boils were on the magicians and on all the Egyptians.

12The LORD hardened the heart of Pharaoh, and he didn’t listen to them, as the LORD had spoken to Moses.

13The LORD said to Moses, “Rise up early in the morning, and stand before Pharaoh, and tell him, ‘This is what the LORD, the God of the Hebrews, says: “Let my people go, that they may serve me.

14For this time I will send all my plagues against your heart, against your officials, and against your people; that you may know that there is no one like me in all the earth.