Exodus 9:10-12

King James Version

¹⁰ And they took ashes of the furnace, and stood before Pharaoh; and Moses sprinkled it up toward heaven; and it became a boil breaking forth with blains upon man, and upon beast.

¹¹ And the magicians could not stand before Moses because of the boils; for the boil was upon the magicians, and upon all the Egyptians.

¹² And the Lord hardened the heart of Pharaoh, and he hearkened not unto them; as the Lord had spoken unto Moses.